Apply suggestions from code review

Co-Authored-By: Erick Zhao <erick@hotmail.ca>

.travis.yml

@@ -1,10 +1,10 @@
 language: node_js
-node_js: "8"
+node_js: "12"
 os:
 - linux
 - osx
 dist: trusty
-osx_image: xcode8.3
+osx_image: xcode10
 sudo: false
 
 cache:

CONTRIBUTING.md

@@ -0,0 +1,57 @@
+# Contributing to Electron Fiddle
+
+Electron Fiddle is a community-driven project, overseen by the [Electron Ecosystem Working
+Group](https://github.com/electron/governance/tree/master/wg-ecosystem#readme). As such, we welcome
+and encourage all sorts of contributions. They include, but are not limited to:
+
+- Constructive feedback
+- Bug reports / technical issues
+- Documentation changes
+- Feature requests
+- [Pull requests](#filing-pull-requests)
+
+We strongly suggest that before filing an issue, you search through the existing issues to see
+if it has already been filed by someone else.
+
+This project is a part of the Electron ecosystem. As such, all contributions to this project follow
+[Electron's code of conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md)
+where appropriate.
+
+## Contribution Suggestions
+
+We use the label [`good first issue`](https://github.com/electron/fiddle/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) in the issue tracker to denote fairly-well-scoped-out bugs or feature requests that the community can pick up and work on. If any of those labeled issues do not have enough information, please feel free to ask constructive questions. (This applies to any open issue.)
+
+## Filing Pull Requests
+
+Here are some things to keep in mind as you file pull requests to fix bugs, add new features, etc.:
+
+* If you're unfamiliar with forking, branching, and pull requests, please see [GitHub's extensive
+  documentation](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests).
+* Travis CI and AppVeyor are used to make sure that any new or changed code meets the project's
+  style guidelines, and that the project's testsuite passes for each new commit.
+* Unless it's impractical, please write tests for your changes. This will help us so that we can
+  spot regressions much easier.
+* When creating commit messages and pull request titles, please adhere to the [conventional
+  commits](https://www.conventionalcommits.org/en/v1.0.0/) standard.
+* Please **do not** bump the version number in your pull requests, the maintainers will do that.
+  Feel free to indicate whether the changes require a major, minor, or patch version bump, as
+  prescribed by the [semantic versioning specification](http://semver.org/).
+
+### Running Fiddle From Source
+
+```sh
+git clone https://github.com/electron/fiddle
+cd fiddle
+npm install
+npm start
+```
+
+### Running Tests
+
+```sh
+npm test
+```
+
+## Release Process
+
+<!-- TODO @felix add your release process here 😁 -->

LICENSE.md

@@ -1,4 +1,4 @@
-Copyright (c) 2013-2018 GitHub Inc.
+Copyright (c) 2013-2020 GitHub Inc.
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
@@ -17,4 +17,4 @@ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -5,8 +5,8 @@
 Electron Fiddle lets you create and play with small Electron experiments. It
 greets you with a quick-start template after opening – change a few things,
 choose the version of Electron you want to run it with, and play around. Then,
-save your Fiddle either as a GitHub Gist or to a local folder. Once pushed to
-GitHub, anyone can quickly try your Fiddle out by just entering it in the
+save your Fiddle either as a GitHub Gist or to a local folder. Once published
+on GitHub, anyone can quickly try your Fiddle out by just entering it in the
 address bar.
 
 <h3 align="center">
@@ -15,13 +15,13 @@ address bar.
   </a>
 </h3>
 
-<img src="https://user-images.githubusercontent.com/378023/49716908-7d2b0500-fc98-11e8-8f52-def504802509.png" width="880px" alt="Electron Fiddle screenshot">
+<img src="https://user-images.githubusercontent.com/1426799/52155868-d3357c80-2639-11e9-9496-fa97b1dc7897.jpg" width="880px" alt="Electron Fiddle screenshot">
 
 # Features
 
 ### Explore Electron
 
-![Screenshot: Electron App running](https://user-images.githubusercontent.com/1426799/43873856-5f66e56e-9b3d-11e8-8472-3a14d6a08c62.png)
+![Screenshot: Electron App running](https://user-images.githubusercontent.com/1426799/52155856-c0bb4300-2639-11e9-9962-a6354d08dc5a.jpg)
 
 Try Electron without installing any dependencies: Fiddle includes everything
 you'll need to explore the platform. It also includes examples for every API
@@ -40,7 +40,7 @@ all Electron APIs only a few keystrokes away.
 
 ### Compile and Package
 
-![Screenshot: Fiddle's Tasks Menu](https://user-images.githubusercontent.com/1426799/43874349-3f5abd74-9b40-11e8-9225-ddd1f1087a47.png)
+![Screenshot: Fiddle's Tasks Menu](https://user-images.githubusercontent.com/1426799/52155857-c0bb4300-2639-11e9-8776-e05dc528439c.png)
 
 Fiddle can automatically turn your experiment into binaries you can share with
 your friends, coworkers, or grandparents. It does so thanks to

appveyor.yml

@@ -1,6 +1,6 @@
 environment:
   matrix:
-    - nodejs_version: "10"
+    - nodejs_version: "12"
 
 init:
 - git config --global core.symlinks true

forge.config.js

@@ -7,7 +7,7 @@ const packageJson = require('./package.json')
 const { version } = packageJson
 const iconDir = path.resolve(__dirname, 'assets', 'icons')
 
-module.exports = {
+const config = {
   hooks: {
     generateAssets: require('./tools/generateAssets')
   },
@@ -32,7 +32,12 @@ module.exports = {
       OriginalFilename: 'Electron Fiddle',
     },
     osxSign: {
-      identity: 'Developer ID Application: Felix Rieseberg (LT94ZKYDCJ)'
+      identity: 'Developer ID Application: Felix Rieseberg (LT94ZKYDCJ)',
+      'hardened-runtime': true,
+      'gatekeeper-assess': false,
+      'entitlements': 'static/entitlements.plist',
+      'entitlements-inherit': 'static/entitlements.plist',
+      'signature-flags': 'library'
     }
   },
   makers: [
@@ -90,8 +95,36 @@ module.exports = {
           name: 'fiddle'
         },
         draft: true,
-        prerelease: true
+        prerelease: false
       }
     }
   ]
 }
+
+function notarizeMaybe() {
+  if (process.platform !== 'darwin') {
+    return;
+  }
+
+  if (!process.env.CI) {
+    console.log(`Not in CI, skipping notarization`);
+    return;
+  }
+
+  if (!process.env.APPLE_ID || !process.env.APPLE_ID_PASSWORD) {
+    console.warn('Should be notarizing, but environment variables APPLE_ID or APPLE_ID_PASSWORD are missing!');
+    return;
+  }
+
+  config.packagerConfig.osxNotarize = {
+    appBundleId: 'com.electron.fiddle',
+    appleId: process.env.APPLE_ID,
+    appleIdPassword: process.env.APPLE_ID_PASSWORD,
+    ascProvider: 'LT94ZKYDCJ'
+  }
+}
+
+notarizeMaybe()
+
+// Finally, export it
+module.exports = config

jest.json

@@ -1,13 +1,15 @@
 {
   "transform": {
-    ".(js|jsx|ts|tsx)": "ts-jest"
+    "\\.(js|jsx|ts|tsx)$": "ts-jest"
   },
   "testURL": "http://localhost",
   "testRegex": "(-spec)\\.(ts|tsx)$",
   "bail": true,
   "resetMocks": true,
   "resetModules": true,
-  "setupTestFrameworkScriptFile": "<rootDir>/tests/setup.js",
+  "setupFilesAfterEnv": [
+    "<rootDir>/tests/setup.js"
+  ],
   "moduleFileExtensions": [
     "js",
     "jsx",

package.json

@@ -1,18 +1,18 @@
 {
   "name": "electron-fiddle",
   "productName": "Electron Fiddle",
-  "version": "0.5.0",
+  "version": "0.12.0",
   "description": "The easiest way to get started with Electron",
   "repository": "https://github.com/electron/fiddle",
   "main": "./dist/src/main/main",
   "scripts": {
     "contributors": "node ./tools/contributors.js",
     "less": "node ./tools/lessc.js",
-    "lint:style": "stylelint ./src/less/*.less --fix",
+    "lint:style": "stylelint  \"./src/less/*.less\" --fix",
     "lint:ts": "tslint -c tslint.json -p tsconfig.json -e \"node_modules/**/*.ts\" --fix",
-    "lint:tests": "tslint ./tests/**/*.ts{,x} -c tslint.json --fix",
-    "lint:templates": "standard ./static/templates/**/*.js",
-    "lint": "npm-run-all lint:*",
+    "lint:tests": "tslint \"./tests/**/*.ts{,x}\" -c tslint.json --fix",
+    "lint:templates": "standard \"./static/show-me/**/*.js\"",
+    "lint": "npm-run-all \"lint:*\"",
     "make": "electron-forge make",
     "package": "electron-forge package",
     "parcel:build": "node ./tools/parcel-build.js",
@@ -36,71 +36,72 @@
     "forge": "./forge.config.js"
   },
   "dependencies": {
-    "@blueprintjs/core": "^3.10.0",
-    "@blueprintjs/select": "^3.4.0",
-    "@octokit/rest": "^15.12.1",
-    "builtin-modules": "^3.0.0",
+    "@blueprintjs/core": "^3.22.3",
+    "@blueprintjs/select": "^3.11.2",
+    "@octokit/rest": "^16.36.0",
     "classnames": "^2.2.6",
     "electron-default-menu": "^1.0.1",
+    "electron-devtools-installer": "^2.2.4",
     "electron-download": "^4.1.1",
     "electron-squirrel-startup": "^1.0.0",
     "extract-zip": "^1.6.7",
     "fix-path": "^2.1.0",
-    "fs-extra": "^7.0.1",
-    "mobx": "^5.8.0",
-    "mobx-react": "^5.4.3",
-    "monaco-loader": "^0.15.0",
-    "namor": "^1.1.1",
-    "react": "^16.7.0",
-    "react-dom": "^16.7.0",
-    "react-mosaic-component": "^2.0.2",
-    "semver": "^5.6.0",
-    "tmp": "0.0.33",
-    "tslib": "^1.9.3",
-    "update-electron-app": "^1.3.0"
+    "fs-extra": "^8.1.0",
+    "mobx": "^5.15.2",
+    "mobx-react": "^6.1.5",
+    "monaco-editor": "^0.19.2",
+    "monaco-loader": "1.0.0",
+    "namor": "^1.1.3",
+    "react": "^16.12.0",
+    "react-dom": "^16.12.0",
+    "react-mosaic-component": "^3.2.0",
+    "semver": "^7.1.1",
+    "tmp": "0.1.0",
+    "tslib": "^1.10.0",
+    "update-electron-app": "^1.5.0"
   },
   "devDependencies": {
-    "@electron-forge/cli": "^6.0.0-beta.32",
-    "@electron-forge/maker-deb": "^6.0.0-beta.32",
-    "@electron-forge/maker-rpm": "^6.0.0-beta.32",
-    "@electron-forge/maker-squirrel": "^6.0.0-beta.32",
-    "@electron-forge/maker-zip": "^6.0.0-beta.32",
-    "@electron-forge/publisher-github": "^6.0.0-beta.32",
-    "@types/builtin-modules": "^2.0.0",
-    "@types/classnames": "^2.2.7",
-    "@types/enzyme": "^3.1.13",
-    "@types/fs-extra": "^5.0.4",
-    "@types/jest": "^23.3.2",
-    "@types/log-symbols": "^2.0.0",
-    "@types/node": "^10.11.1",
-    "@types/react": "^16.7.18",
-    "@types/react-dom": "^16.0.11",
-    "@types/semver": "^5.5.0",
-    "@types/tmp": "0.0.33",
-    "chokidar": "^2.0.4",
-    "coveralls": "^3.0.2",
-    "electron": "4.0.2",
-    "enzyme": "^3.6.0",
-    "enzyme-adapter-react-16": "^1.5.0",
-    "enzyme-to-json": "^3.3.5",
-    "jest": "^23.6.0",
-    "jest-fetch-mock": "^1.6.6",
-    "less": "^3.8.1",
-    "log-symbols": "^2.2.0",
-    "monaco-editor": "^0.15.6",
-    "node-abi": "^2.5.1",
-    "node-fetch": "^2.3.0",
+    "@babel/core": "^7.8.0",
+    "@electron-forge/cli": "^6.0.0-beta.47",
+    "@electron-forge/maker-deb": "^6.0.0-beta.47",
+    "@electron-forge/maker-rpm": "^6.0.0-beta.47",
+    "@electron-forge/maker-squirrel": "^6.0.0-beta.47",
+    "@electron-forge/maker-zip": "^6.0.0-beta.47",
+    "@electron-forge/publisher-github": "^6.0.0-beta.47",
+    "@sentry/electron": "^1.2.0",
+    "@types/classnames": "^2.2.9",
+    "@types/enzyme": "^3.10.4",
+    "@types/fs-extra": "^8.0.1",
+    "@types/jest": "^24.0.25",
+    "@types/log-symbols": "^3.0.0",
+    "@types/node": "^12.11.7",
+    "@types/react": "^16.9.11",
+    "@types/react-dom": "^16.9.3",
+    "@types/semver": "^6.0.2",
+    "@types/tmp": "0.1.0",
+    "chokidar": "^3.3.1",
+    "coveralls": "^3.0.9",
+    "electron": "7.1.8",
+    "enzyme": "^3.11.0",
+    "enzyme-adapter-react-16": "^1.15.2",
+    "enzyme-to-json": "^3.4.3",
+    "jest": "^24.9.0",
+    "jest-fetch-mock": "^2.1.2",
+    "less": "^3.10.3",
+    "log-symbols": "^3.0.0",
+    "node-abi": "^2.13.0",
+    "node-fetch": "^2.6.0",
     "npm-run-all": "^4.1.5",
-    "parcel-bundler": "^1.11.0",
-    "react-test-renderer": "^16.7.0",
-    "rimraf": "^2.6.3",
-    "standard": "^12.0.1",
-    "stylelint": "^9.9.0",
-    "stylelint-config-standard": "^18.2.0",
-    "ts-jest": "^23.10.5",
-    "tslint": "^5.12.0",
-    "tslint-microsoft-contrib": "^6.0.0",
-    "tslint-react": "^3.6.0",
-    "typescript": "^3.2.2"
+    "parcel-bundler": "^1.12.4",
+    "react-test-renderer": "^16.12.0",
+    "rimraf": "^3.0.0",
+    "standard": "^14.3.1",
+    "stylelint": "^13.0.0",
+    "stylelint-config-standard": "^19.0.0",
+    "ts-jest": "^24.3.0",
+    "tslint": "^5.20.1",
+    "tslint-microsoft-contrib": "^6.2.0",
+    "tslint-react": "^4.1.0",
+    "typescript": "^3.7.4"
   }
 }

src/content/main-1-x-x.ts

@@ -3,13 +3,9 @@ const {app, BrowserWindow} = require('electron')
 const path = require('path')
 const url = require('url')
 
-// Keep a global reference of the window object, if you don't, the window will
-// be closed automatically when the JavaScript object is garbage collected.
-let mainWindow
-
 function createWindow () {
   // Create the browser window.
-  mainWindow = new BrowserWindow({width: 800, height: 600})
+  const mainWindow = new BrowserWindow({width: 800, height: 600})
 
   // and load the index.html of the app.
   mainWindow.loadURL(url.format({
@@ -20,14 +16,6 @@ function createWindow () {
 
   // Open the DevTools.
   // mainWindow.webContents.openDevTools()
-
-  // Emitted when the window is closed.
-  mainWindow.on('closed', function () {
-    // Dereference the window object, usually you would store windows
-    // in an array if your app supports multi windows, this is the time
-    // when you should delete the corresponding element.
-    mainWindow = null
-  })
 }
 
 // This method will be called when Electron has finished
@@ -47,7 +35,7 @@ app.on('window-all-closed', function () {
 app.on('activate', function () {
   // On OS X it's common to re-create a window in the app when the
   // dock icon is clicked and there are no other windows open.
-  if (mainWindow === null) {
+  if (BrowserWindow.getAllWindows().length === 0) {
     createWindow()
   }
 })

src/content/main.ts

@@ -1,13 +1,9 @@
 export const main = `// Modules to control application life and create native browser window
 const {app, BrowserWindow} = require('electron')
 
-// Keep a global reference of the window object, if you don't, the window will
-// be closed automatically when the JavaScript object is garbage collected.
-let mainWindow
-
 function createWindow () {
   // Create the browser window.
-  mainWindow = new BrowserWindow({
+  const mainWindow = new BrowserWindow({
     width: 800,
     height: 600,
     webPreferences: {
@@ -20,14 +16,6 @@ function createWindow () {
 
   // Open the DevTools.
   // mainWindow.webContents.openDevTools()
-
-  // Emitted when the window is closed.
-  mainWindow.on('closed', function () {
-    // Dereference the window object, usually you would store windows
-    // in an array if your app supports multi windows, this is the time
-    // when you should delete the corresponding element.
-    mainWindow = null
-  })
 }
 
 // This method will be called when Electron has finished
@@ -47,7 +35,7 @@ app.on('window-all-closed', function () {
 app.on('activate', function () {
   // On OS X it's common to re-create a window in the app when the
   // dock icon is clicked and there are no other windows open.
-  if (mainWindow === null) {
+  if (BrowserWindow.getAllWindows().length === 0) {
     createWindow()
   }
 })

src/interfaces.ts

@@ -24,6 +24,7 @@ export interface EditorValues {
   main: string;
   renderer: string;
   html: string;
+  preload: string;
   package?: string;
 }
 
@@ -32,6 +33,12 @@ export interface ElectronVersion extends NpmVersion {
   source: ElectronVersionSource;
 }
 
+export interface SetFiddleOptions {
+  filePath?: string;
+  templateName?: string;
+  gistId?: string;
+}
+
 export interface OutputEntry {
   text: string;
   timestamp: number;
@@ -43,7 +50,8 @@ export interface OutputOptions {
   isNotPre?: boolean;
 }
 
-export interface WarningDialogTexts {
+export interface GenericDialogOptions {
+  type: GenericDialogType;
   ok?: string;
   cancel?: string;
   label: string;
@@ -53,6 +61,34 @@ export interface Templates {
   [index: string]: string | Templates;
 }
 
-export type EditorId = 'main' | 'renderer' | 'html';
+export const enum GenericDialogType {
+  'confirm' = 'confirm',
+  'warning' = 'warning',
+  'success' = 'success',
+}
+
+// Editors
+export const enum EditorId {
+  'main' = 'main',
+  'renderer' = 'renderer',
+  'html' = 'html',
+  'preload' = 'preload'
+}
+
+// Panels that can show up as a mosaic
+export const enum PanelId {
+  'docsDemo' = 'docsDemo'
+}
+
+export type MosaicId = EditorId | PanelId;
+
+export const ALL_EDITORS =  [ EditorId.main, EditorId.renderer, EditorId.preload, EditorId.html ];
+export const ALL_PANELS = [ PanelId.docsDemo ];
+export const ALL_MOSAICS = [ ...ALL_EDITORS, ...ALL_PANELS ];
 
 export type ArrowPosition = 'top' | 'left' | 'bottom' | 'right';
+
+export const enum DocsDemoPage {
+  DEFAULT = 'DEFAULT',
+  DEMO_APP = 'DEMO_APP'
+}

src/ipc-events.ts

@@ -1,6 +1,7 @@
 export enum IpcEvents {
   OPEN_SETTINGS = 'OPEN_SETTINGS',
   LOAD_GIST_REQUEST = 'LOAD_GIST_REQUEST',
+  LOAD_ELECTRON_EXAMPLE_REQUEST = 'LOAD_ELECTRON_EXAMPLE_REQUEST',
   FIDDLE_RUN = 'FIDDLE_RUN',
   FIDDLE_PACKAGE = 'FIDDLE_PACKAGE',
   FIDDLE_MAKE = 'FIDDLE_MAKE',
@@ -16,18 +17,26 @@ export enum IpcEvents {
   FS_SAVE_FIDDLE_DIALOG = 'FS_SAVE_FIDDLE_DIALOG',
   FS_SAVE_FIDDLE_ERROR = 'FS_SAVE_FIDDLE_ERROR',
   SHOW_WARNING_DIALOG = 'SHOW_WARNING_DIALOG',
-  SHOW_WELCOME_TOUR = 'SHOW_WELCOME_TOUR'
+  SHOW_CONFIRMATION_DIALOG = 'SHOW_CONFIRMATION_DIALOG',
+  SHOW_WELCOME_TOUR = 'SHOW_WELCOME_TOUR',
+  CLEAR_CONSOLE = 'CLEAR_CONSOLE',
+  LOAD_LOCAL_VERSION_FOLDER = 'LOAD_LOCAL_VERSION_FOLDER',
+  SHOW_LOCAL_VERSION_FOLDER_DIALOG = 'SHOW_LOCAL_VERSION_FOLDER_DIALOG',
+  BISECT_COMMANDS_TOGGLE = 'BISECT_COMMANDS_TOGGLE',
 }
 
 export const ipcMainEvents = [
   IpcEvents.FS_SAVE_FIDDLE_DIALOG,
   IpcEvents.FS_SAVE_FIDDLE,
-  IpcEvents.SHOW_WARNING_DIALOG
+  IpcEvents.SHOW_WARNING_DIALOG,
+  IpcEvents.SHOW_CONFIRMATION_DIALOG,
+  IpcEvents.SHOW_LOCAL_VERSION_FOLDER_DIALOG
 ];
 
 export const ipcRendererEvents = [
   IpcEvents.OPEN_SETTINGS,
   IpcEvents.LOAD_GIST_REQUEST,
+  IpcEvents.LOAD_ELECTRON_EXAMPLE_REQUEST,
   IpcEvents.FIDDLE_RUN,
   IpcEvents.FIDDLE_PACKAGE,
   IpcEvents.FIDDLE_MAKE,
@@ -40,5 +49,10 @@ export const ipcRendererEvents = [
   IpcEvents.FS_SAVE_FIDDLE_AS,
   IpcEvents.FS_SAVE_FIDDLE_FORGE,
   IpcEvents.FS_SAVE_FIDDLE_GIST,
-  IpcEvents.SHOW_WELCOME_TOUR
+  IpcEvents.SHOW_WELCOME_TOUR,
+  IpcEvents.CLEAR_CONSOLE,
+  IpcEvents.LOAD_LOCAL_VERSION_FOLDER,
+  IpcEvents.BISECT_COMMANDS_TOGGLE
 ];
+
+export const WEBCONTENTS_READY_FOR_IPC_SIGNAL = 'WEBCONTENTS_READY_FOR_IPC_SIGNAL';

src/less/blueprint.less

@@ -18,6 +18,15 @@
     background-color: @background-1;
   }
 
+  .bp3-button.bp3-minimal {
+    background-color: unset;
+  }
+
+  .bp3-button:hover,
+  .bp3-button.bp3-minimal:hover {
+    background-color: rgba(138, 155, 168, 0.15);
+  }
+
   .bp3-menu-item.bp3-active.bp3-intent-primary {
     background-color: @foreground-3;
   }
@@ -29,4 +38,8 @@
       background-color: @background-3;
     }
   }
+
+  .bp3-running-text {
+    font-size: 14px;
+  }
 }

src/less/components/commands-version-chooser.less

@@ -1,3 +0,0 @@
-button.version-chooser.bp3-button {
-  border-radius: 3px 0 0 3px;
-}

src/less/components/commands.less

@@ -2,7 +2,6 @@
 
 header {
   box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.2), 0 0 0 rgba(16, 22, 26, 0), 0 1px 1px rgba(16, 22, 26, 0.4);
-  //border-bottom: 1px solid rgba(255, 255, 255, 0.1);
   background-color: @background-3;
   -webkit-app-region: drag;
 }
@@ -20,6 +19,7 @@ header {
   select {
     -webkit-app-region: no-drag;
     margin-bottom: 0;
+    white-space: nowrap;
   }
 
   select {
@@ -27,6 +27,13 @@ header {
     margin-left: 5px;
   }
 
+  fieldset {
+    border: 0;
+    padding: 0;
+    margin: 0;
+    min-width: 0;
+  }
+
   & > div {
     display: flex;
 

src/less/components/editors.less

@@ -2,6 +2,43 @@
   animation: fadein 0.15s;
 }
 
+.mosaic-window-toolbar  {
+  & > div {
+    display: flex;
+    justify-content: space-between;
+    width: 100%;
+    padding: 0 5px 0 5px;
+
+    .mosaic-controls {
+      transform: scale(0.75);
+      transform-origin: right;
+    }
+
+    h5 {
+      margin: 4px 0 0 0;
+    }
+
+    button {
+      margin-left: 8px;
+    }
+  }
+}
+
+// update if list of Editor ID changes
+@editor-ids: main, renderer, html, preload;
+
+// takes each editor ID and increase its z-index if the parent Mosiac root
+// has focused__id class for that specific id.
+each(@editor-ids, {
+  .focused__@{value}.mosaic .mosaic-window.@{value} {
+    z-index: 2;
+  }
+});
+
+.mosaic-window {
+  z-index: 1;
+}
+
 @keyframes fadein {
   from { opacity: 0; }
   to { opacity: 1; }

src/less/components/mosaic.less

@@ -1,7 +1,7 @@
 @import "../variables.less";
 
 .fiddle {
-  .mosaic-window-toolbar.draggable {
+  .mosaic-window-toolbar {
     background: var(--background-1);
     box-shadow: inset 0 0 100px 100px rgba(53, 53, 53, 0.1);
     border-top: 1px solid rgba(255, 255, 255, 0.1);
@@ -34,9 +34,9 @@
     flex-wrap: nowrap;
     align-items: stretch;
     align-content: stretch;
-    font-size: 12px;
     overflow: visible;
     z-index: 4;
+    background-color: @background-4;
   }
 
   .mosaic {

src/less/components/output.less

@@ -7,20 +7,15 @@
   color: var(--text-color-1);
   background: var(--background-2);
   box-shadow: inset 0 0 100px 100px rgba(0, 0, 0, 0.15);
+  border-top: @border;
   top: 10vh;
   padding: 0;
+  padding-top: 10px;
   padding-left: 10px;
-  height: 0;
+  height: 100%;
   overflow-y: scroll;
-  transition: height 0.2s linear, padding 0.2s linear;
   -webkit-app-region: no-drag;
 
-  &.showing {
-    border-top: @border;
-    padding-top: 10px;
-    height: 150px;
-  }
-
   p {
     margin-bottom: 0;
     white-space: pre;

src/less/components/show-me.less

@@ -0,0 +1,21 @@
+.show-me-panel {
+  padding: 10px;
+  overflow: scroll;
+
+  & > *:first-child {
+    margin-top: 0;
+  };
+
+  .bp3-callout {
+    margin-bottom: 10px;
+  }
+}
+
+.show-me-list {
+  display: flex;
+  flex-direction: column;
+  flex-wrap: wrap;
+  list-style: none;
+  padding: 0;
+  max-height: 400px;
+}

src/less/components/version-select.less

@@ -0,0 +1,5 @@
+.bp3-fill {
+  .version-chooser  {
+    width: 100%;
+  }
+}

src/less/mosaic-vendor.less

@@ -188,7 +188,6 @@
   position: relative;
   display: flex;
   flex-direction: column;
-  overflow: hidden;
   box-shadow: 0 0 1px rgba(0, 0, 0, 0.2);
 }
 

src/less/root.less

@@ -3,7 +3,6 @@
 
 // Variables, also imported in each file
 @import "variables.less";
-
 @import "main.less";
 @import "container.less";
 @import "mosaic-vendor.less";
@@ -17,4 +16,5 @@
 @import "components/chrome-mac.less";
 @import "components/editors.less";
 @import "components/tour.less";
-@import "components/commands-version-chooser.less";
+@import "components/show-me.less";
+@import "components/version-select.less";

src/main/context-menu.ts

@@ -15,6 +15,11 @@ export function getRunItems(): Array<MenuItemConstructorOptions> {
       label: 'Run Fiddle',
       click: () => ipcMainManager.send(IpcEvents.FIDDLE_RUN)
     },
+    {
+      id: 'clear_console',
+      label: 'Clear Console',
+      click: () => ipcMainManager.send(IpcEvents.CLEAR_CONSOLE)
+    },
     {
       type: 'separator'
     }
@@ -136,17 +141,17 @@ export function createContextMenu(browserWindow: BrowserWindow) {
       {
         id: 'cut',
         label: 'Cut',
-        role: editFlags.canCut ? 'cut' : '',
+        role: 'cut',
         enabled: editFlags.canCut
       }, {
         id: 'copy',
         label: 'Copy',
-        role: editFlags.canCopy ? 'copy' : '',
+        role: 'copy',
         enabled: editFlags.canCopy
       }, {
         id: 'paste',
         label: 'Paste',
-        role: editFlags.canPaste ? 'paste' : '',
+        role: 'paste',
         enabled: editFlags.canPaste
       }, {
         type: 'separator'

src/main/devtools.ts

@@ -0,0 +1,27 @@
+import { isDevMode } from '../utils/devmode';
+
+/**
+ * Installs developer tools if we're in dev mode.
+ *
+ * @export
+ * @returns {Promise<void>}
+ */
+export async function setupDevTools(): Promise<void> {
+  if (!isDevMode()) return;
+
+  const {
+    default: installExtension,
+    REACT_DEVELOPER_TOOLS,
+    REACT_PERF
+  } = require('electron-devtools-installer');
+
+  try {
+    const react = await installExtension(REACT_DEVELOPER_TOOLS);
+    console.log(`installDevTools: Installed ${react}`);
+
+    const perf = await installExtension(REACT_PERF);
+    console.log(`installDevTools: Installed ${perf}`);
+  } catch (error) {
+    console.warn(`installDevTools: Error occured:`, error);
+  }
+}

src/main/dialogs.ts

@@ -1,4 +1,4 @@
-import { dialog } from 'electron';
+import { dialog, IpcMainEvent } from 'electron';
 import { IpcEvents } from '../ipc-events';
 import { ipcMainManager } from './ipc';
 import { getOrCreateMainWindow } from './windows';
@@ -12,6 +12,15 @@ export function setupDialogs() {
   ipcMainManager.on(IpcEvents.SHOW_WARNING_DIALOG, (_event, args) => {
     showWarningDialog(args);
   });
+
+  ipcMainManager.on(IpcEvents.SHOW_CONFIRMATION_DIALOG, (_event, args) => {
+    showConfirmationDialog(args);
+  });
+
+  ipcMainManager.on(IpcEvents.SHOW_LOCAL_VERSION_FOLDER_DIALOG, async (event) => {
+    await showOpenDialog(event);
+  });
+
 }
 
 /**
@@ -25,3 +34,28 @@ function showWarningDialog(args: Electron.MessageBoxOptions) {
     ...args
   });
 }
+
+/**
+ * Shows a confirmation dialog
+ *
+ * @param {Electron.MessageBoxOptions} args
+ */
+function showConfirmationDialog(args: Electron.MessageBoxOptions) {
+  dialog.showMessageBox(getOrCreateMainWindow(), {
+    type: 'warning',
+    ...args
+  });
+}
+
+async function showOpenDialog(event: IpcMainEvent) {
+  const { filePaths } = await dialog.showOpenDialog({
+    title: 'Open Folder',
+    properties: ['openDirectory']
+  });
+
+  if (!filePaths || filePaths.length < 1) {
+    return;
+  }
+
+  event.reply(IpcEvents.LOAD_LOCAL_VERSION_FOLDER, [filePaths[0]]);
+}

src/main/files.ts

@@ -19,41 +19,41 @@ export function setupFileListeners() {
  * Shows the "Open Fiddle" dialog and forwards
  * the path to the renderer
  */
-export function showOpenDialog() {
-  dialog.showOpenDialog({
+export async function showOpenDialog() {
+  const { filePaths } = await dialog.showOpenDialog({
     title: 'Open Fiddle',
     properties: ['openDirectory']
-  }, (filePaths) => {
-    if (!filePaths || filePaths.length < 1) {
-      return;
-    }
-
-    ipcMainManager.send(IpcEvents.FS_OPEN_FIDDLE, [ filePaths[0] ]);
   });
+
+  if (!filePaths || filePaths.length < 1) {
+    return;
+  }
+
+  ipcMainManager.send(IpcEvents.FS_OPEN_FIDDLE, [ filePaths[0] ]);
 }
 
 /**
  * Shows the "Save Fiddle" dialog and forwards
  * the path to the renderer
  */
-export function showSaveDialog(event?: IpcEvents, as?: string) {
+export async function showSaveDialog(event?: IpcEvents, as?: string) {
   // We want to save to a folder, so we'll use an open dialog here
-  dialog.showOpenDialog({
+  const { filePaths } = await dialog.showOpenDialog({
     buttonLabel: 'Save here',
     properties: ['openDirectory', 'createDirectory'],
     title: `Save Fiddle${as ? ` as ${as}` : ''}`
-  }, async (filePaths) => {
-    if (!filePaths || filePaths.length < 1) {
-      return;
-    }
-
-    console.log(`Asked to save to ${filePaths[0]}`);
-
-    // Let's confirm real quick if we want this
-    if (await ensureSaveTargetEmpty(filePaths[0])) {
-      ipcMainManager.send(event || IpcEvents.FS_SAVE_FIDDLE, [ filePaths[0] ]);
-    }
   });
+
+  if (!filePaths || filePaths.length < 1) {
+    return;
+  }
+
+  console.log(`Asked to save to ${filePaths[0]}`);
+
+  // Let's confirm real quick if we want this
+  if (await ensureSaveTargetEmpty(filePaths[0])) {
+    ipcMainManager.send(event || IpcEvents.FS_SAVE_FIDDLE, [ filePaths[0] ]);
+  }
 }
 
 /**

src/main/first-run.ts

@@ -7,9 +7,9 @@ import { isDevMode } from '../utils/devmode';
  * Is this the first run of Fiddle? If so, perform
  * tasks that we only want to do in this case.
  */
-export function onFirstRunMaybe() {
+export async function onFirstRunMaybe() {
   if (isFirstRun()) {
-    promptMoveToApplicationsFolder();
+    await promptMoveToApplicationsFolder();
   }
 }
 
@@ -17,18 +17,18 @@ export function onFirstRunMaybe() {
  * Ask the user if the app should be moved to the
  * applications folder.
  */
-function promptMoveToApplicationsFolder(): void {
+async function promptMoveToApplicationsFolder(): Promise<void> {
   if (process.platform !== 'darwin') return;
   if (isDevMode() || app.isInApplicationsFolder()) return;
 
-  dialog.showMessageBox({
+  const { response } = await dialog.showMessageBox({
     type: 'question',
     buttons: ['Move to Applications Folder', 'Do Not Move'],
     defaultId: 0,
     message: 'Move to Applications Folder?',
-  }, (response) => {
-    if (response === 0) {
-      app.moveToApplicationsFolder();
-    }
   });
+
+  if (response === 0) {
+    app.moveToApplicationsFolder();
+  }
 }

src/main/ipc.ts

@@ -1,6 +1,7 @@
 import { ipcMain } from 'electron';
 import { EventEmitter } from 'events';
-import { IpcEvents, ipcMainEvents } from '../ipc-events';
+
+import { IpcEvents, ipcMainEvents, WEBCONTENTS_READY_FOR_IPC_SIGNAL } from '../ipc-events';
 import { getOrCreateMainWindow } from './windows';
 
 /**
@@ -12,12 +13,26 @@ import { getOrCreateMainWindow } from './windows';
  * @extends {EventEmitter}
  */
 export class IpcMainManager extends EventEmitter {
+  public readyWebContents = new WeakSet<Electron.WebContents>();
+  private messageQueue = new WeakMap<Electron.WebContents, Array<[IpcEvents, Array<any> | undefined]>>();
+
   constructor() {
     super();
 
     ipcMainEvents.forEach((name) => {
       ipcMain.on(name, (...args: Array<any>) => this.emit(name, ...args));
     });
+
+    ipcMain.on(WEBCONTENTS_READY_FOR_IPC_SIGNAL, (event: Electron.IpcMainEvent) => {
+      this.readyWebContents.add(event.sender);
+
+      const queue = this.messageQueue.get(event.sender);
+      this.messageQueue.delete(event.sender);
+      if (!queue) return;
+      for (const item of queue) {
+        this.send(item[0], item[1], event.sender);
+      }
+    });
   }
 
   /**
@@ -31,6 +46,11 @@ export class IpcMainManager extends EventEmitter {
   public send(channel: IpcEvents, args?: Array<any>, target?: Electron.WebContents) {
     const _target = target || getOrCreateMainWindow().webContents;
     const _args = args || [];
+    if (!this.readyWebContents.has(_target)) {
+      const existing = this.messageQueue.get(_target) || [];
+      this.messageQueue.set(_target, [...existing, [channel, args]]);
+      return;
+    }
 
     _target.send(channel, ..._args);
   }

src/main/main.ts

@@ -1,6 +1,11 @@
+import * as Sentry from '@sentry/electron';
+Sentry.init({dsn: 'https://966a5b01ac8d4941b81e4ebd0ab4c991@sentry.io/1882540'});
+
 import { app } from 'electron';
 
 import { isDevMode } from '../utils/devmode';
+import { setupAboutPanel } from '../utils/set-about-panel';
+import { setupDevTools } from './devtools';
 import { setupDialogs } from './dialogs';
 import { onFirstRunMaybe } from './first-run';
 import { listenForProtocolHandler, setupProtocolHandler } from './protocol';
@@ -13,10 +18,11 @@ import { getOrCreateMainWindow } from './windows';
  * the method that takes care of booting the application.
  */
 export async function onReady() {
-  onFirstRunMaybe();
+  await onFirstRunMaybe();
   if (!isDevMode()) process.env.NODE_ENV = 'production';
 
   getOrCreateMainWindow();
+  setupAboutPanel();
 
   const { setupMenu } = await import('./menu');
   const { setupFileListeners } = await import('./files');
@@ -26,6 +32,16 @@ export async function onReady() {
   setupFileListeners();
   setupUpdates();
   setupDialogs();
+  setupDevTools();
+}
+
+/**
+ * Handle the "before-quit" event
+ *
+ * @export
+ */
+export function onBeforeQuit() {
+  (global as any).isQuitting = true;
 }
 
 /**
@@ -55,13 +71,14 @@ export function main() {
   }
 
   // Set the app's name
-  app.setName('Electron Fiddle');
+  app.name = 'Electron Fiddle';
 
   // Ensure that there's only ever one Fiddle running
   listenForProtocolHandler();
 
   // Launch
   app.on('ready', onReady);
+  app.on('before-quit', onBeforeQuit);
   app.on('window-all-closed', onWindowsAllClosed);
   app.on('activate', getOrCreateMainWindow);
 }

src/main/menu.ts

@@ -144,7 +144,7 @@ function getShowMeMenuItem(key: string, item: string | Templates): MenuItemConst
   if (typeof item === 'string') {
     return {
       label: key,
-      click: () => ipcMainManager.send(IpcEvents.FS_OPEN_TEMPLATE, [ key ])
+      click: () => ipcMainManager.send(IpcEvents.FS_OPEN_TEMPLATE, [key])
     };
   }
 
@@ -160,10 +160,10 @@ function getShowMeMenu(): MenuItemConstructorOptions {
   const showMeMenu: Array<MenuItemConstructorOptions> = Object.keys(SHOW_ME_TEMPLATES)
     .map((key) => getShowMeMenuItem(key, SHOW_ME_TEMPLATES[key]));
 
-    return {
-      label: 'Show Me',
-      submenu: showMeMenu
-    };
+  return {
+    label: 'Show Me',
+    submenu: showMeMenu
+  };
 }
 
 /**
@@ -206,7 +206,7 @@ function getFileMenu(): MenuItemConstructorOptions {
       type: 'separator'
     },
     {
-      label: 'Save to Gist',
+      label: 'Publish to Gist',
       click: () => ipcMainManager.send(IpcEvents.FS_SAVE_FIDDLE_GIST),
     },
     {
@@ -248,14 +248,19 @@ export function setupMenu() {
       // Tweak "View" menu
       if (label === 'View' && isSubmenu(item.submenu)) {
         item.submenu = item.submenu.filter((subItem) => subItem.label !== 'Toggle Developer Tools'); // Remove "Toggle Developer Tools"
-        item.submenu.push({ type: 'separator' }, { role: 'resetzoom' }, { role: 'zoomin' }, { role: 'zoomout' }); // Add zooming actions
+        item.submenu.push({ type: 'separator' }, { role: 'resetZoom' }, { role: 'zoomIn' }, { role: 'zoomOut' }); // Add zooming actions
         item.submenu.push({ type: 'separator' }, {
           label: 'Toggle Soft Wrap',
-          click: () => ipcMainManager.send(IpcEvents.MONACO_TOGGLE_OPTION, [ 'wordWrap' ]),
+          click: () => ipcMainManager.send(IpcEvents.MONACO_TOGGLE_OPTION, ['wordWrap']),
         });
         item.submenu.push({ type: 'separator' }, {
           label: 'Toggle Mini Map',
-          click: () => ipcMainManager.send(IpcEvents.MONACO_TOGGLE_OPTION, [ 'minimap.enabled' ]),
+          click: () => ipcMainManager.send(IpcEvents.MONACO_TOGGLE_OPTION, ['minimap.enabled']),
+        });
+        item.submenu.push({ type: 'separator' }, {
+          label: 'Toggle Bisect Helper',
+          click: () => ipcMainManager.send(IpcEvents.BISECT_COMMANDS_TOGGLE),
+          accelerator: 'CommandorControl+Shift+B',
         });
       }
 

src/main/protocol.ts

@@ -4,6 +4,7 @@ import * as path from 'path';
 import * as nodeUrl from 'url';
 
 import { IpcEvents } from '../ipc-events';
+import { isDevMode } from '../utils/devmode';
 import { ipcMainManager } from './ipc';
 
 const PROTOCOL = 'electron-fiddle';
@@ -16,21 +17,61 @@ const handlePotentialProtocolLaunch = (url: string) => {
   }
 
   const parsed = nodeUrl.parse(url.replace(/\/$/, ''));
-  if (!parsed.pathname) return;
+  if (!parsed.pathname || !parsed.hostname) return;
 
-  const pathParts = parsed.pathname.split('/');
-  if (pathParts.length <= 0 || pathParts.length > 2) return;
+  const pathParts = parsed.pathname.split('/').slice(1);
 
-  ipcMainManager.send(IpcEvents.LOAD_GIST_REQUEST, [parsed.pathname]);
+  switch (parsed.hostname) {
+    // electron-fiddle://gist/blub
+    case 'gist':
+      if (pathParts.length === 1) {
+        // We only have a gist ID
+        ipcMainManager.send(IpcEvents.LOAD_GIST_REQUEST, [{
+          id: pathParts[0],
+        }]);
+      } else if (pathParts.length === 2) {
+        // We have a gist owner and gist ID, we can ignore the owner
+        ipcMainManager.send(IpcEvents.LOAD_GIST_REQUEST, [{
+          id: pathParts[1],
+        }]);
+      } else {
+        // This is a super invalid gist launch
+        return;
+      }
+      break;
+    // electron-fiddle://electron/{ref}/{path}
+    case 'electron':
+      if (pathParts.length > 1) {
+        // First part of the commit HASH / ref / branch
+        // Rest is the path to the example
+        ipcMainManager.send(IpcEvents.LOAD_ELECTRON_EXAMPLE_REQUEST, [{
+          ref: pathParts[0],
+          path: pathParts.slice(1).join('/'),
+        }]);
+      } else {
+        // This is an invalid electron launch
+        return;
+      }
+      break;
+    default:
+      return;
+  }
 };
 
 export const scanArgv = (argv: Array<string>) => {
   const protocolArg = argv.find((arg) => arg.startsWith(`${PROTOCOL}://`));
   if (protocolArg) {
+    console.info('Found protocol arg in argv:', protocolArg);
     handlePotentialProtocolLaunch(protocolArg);
   }
 };
 
+export const scanNpmArgv = (argv: string) => {
+  const parsedArgv = JSON.parse(argv);
+  const { original: args } = parsedArgv;
+  scanArgv(args);
+};
+
 export const listenForProtocolHandler = () => {
   const gotTheLock = app.requestSingleInstanceLock();
   if (!gotTheLock) app.quit();
@@ -41,7 +82,10 @@ export const listenForProtocolHandler = () => {
     }
   });
 
-  if (process.platform === 'win32') {
+  // pass protocol URL via npm start args in dev mode
+  if (isDevMode() && process.env.npm_config_argv) {
+    scanNpmArgv(process.env.npm_config_argv);
+  } else if (process.platform === 'win32') {
     scanArgv(process.argv);
   }
 };

src/main/windows.ts

@@ -20,7 +20,8 @@ export function getMainWindowOptions(): Electron.BrowserWindowConstructorOptions
     acceptFirstMouse: true,
     backgroundColor: '#1d2427',
     webPreferences: {
-      webviewTag: false
+      webviewTag: false,
+      nodeIntegration: true
     }
   };
 }

src/renderer/app.tsx

@@ -1,13 +1,29 @@
+import * as Sentry from '@sentry/electron';
+Sentry.init({dsn: 'https://966a5b01ac8d4941b81e4ebd0ab4c991@sentry.io/1882540'});
+
 import { when } from 'mobx';
 import * as MonacoType from 'monaco-editor';
 
-import { EditorValues } from '../interfaces';
+import { ipcRenderer } from 'electron';
+import {
+  ALL_EDITORS,
+  EditorId,
+  EditorValues,
+  GenericDialogType,
+  SetFiddleOptions
+} from '../interfaces';
+import { WEBCONTENTS_READY_FOR_IPC_SIGNAL } from '../ipc-events';
 import { updateEditorLayout } from '../utils/editor-layout';
+import { getEditorValue } from '../utils/editor-value';
 import { getPackageJson, PackageJsonOptions } from '../utils/get-package';
+import { getTitle } from '../utils/get-title';
+import { isEditorBackup } from '../utils/type-checks';
 import { FileManager } from './file-manager';
+import { RemoteLoader } from './remote-loader';
 import { Runner } from './runner';
 import { appState } from './state';
 import { getTheme } from './themes';
+import { TouchBarManager } from './touch-bar-manager';
 
 /**
  * The top-level class controlling the whole app. This is *not* a React component,
@@ -20,49 +36,47 @@ export class App {
   public monaco: typeof MonacoType | null = null;
   public state = appState;
   public fileManager = new FileManager(appState);
+  public remoteLoader = new RemoteLoader(appState);
   public runner = new Runner(appState);
+  public touchBarManager: TouchBarManager | undefined;
 
   constructor() {
-    this.getValues = this.getValues.bind(this);
-    this.setValues = this.setValues.bind(this);
+    this.getEditorValues = this.getEditorValues.bind(this);
+    this.setEditorValues = this.setEditorValues.bind(this);
+
+    if (process.platform === 'darwin') {
+      this.touchBarManager = new TouchBarManager(appState);
+    }
   }
 
-  /**
-   * Sets the values on all three editors.
-   *
-   * @param {EditorValues} values
-   * @param {warn} warn - Should we warn before overwriting unsaved data?
-   */
-  public async setValues(values: Partial<EditorValues>, warn: boolean = true): Promise<boolean> {
-    const { ElectronFiddle: fiddle } = window;
+  public async replaceFiddle(
+    editorValues: Partial<EditorValues>,
+    { filePath, gistId, templateName }: Partial<SetFiddleOptions>
+  ) {
+    // if unsaved, prompt user to make sure they're okay with overwriting and changing directory
+    if (this.state.isUnsaved) {
+      this.state.setGenericDialogOptions({
+        type: GenericDialogType.warning,
+        label: `Opening this Fiddle will replace your unsaved changes. Do you want to proceed?`,
+        ok: 'Yes'
+      });
+      this.state.isGenericDialogShowing = true;
+      await when(() => !this.state.isGenericDialogShowing);
 
-    if (!fiddle) {
-      throw new Error('Fiddle not ready');
-    }
-
-    if (this.state.isUnsaved && warn) {
-      this.state.isWarningDialogShowing = true;
-      await when(() => !this.state.isWarningDialogShowing);
-
-      if (!this.state.warningDialogLastResult) {
+      if (!this.state.genericDialogLastResult) {
         return false;
       }
     }
 
-    const { main, html, renderer } = fiddle.editors;
+    // set values once prompt approves
+    await this.setEditorValues(editorValues);
 
-    if (html && html.setValue && values.html) {
-      html.setValue(values.html);
-    }
-
-    if (main && main.setValue && values.main) {
-      main.setValue(values.main);
-    }
-
-    if (renderer && renderer.setValue && values.renderer) {
-      renderer.setValue(values.renderer);
-    }
+    document.title = getTitle(this.state);
+    this.state.gistId = gistId || '';
+    this.state.localPath = filePath;
+    this.state.templateName = templateName;
 
+    // once loaded, we have a "saved" state
     this.state.isUnsaved = false;
     this.setupUnsavedOnChangeListener();
 
@@ -70,25 +84,62 @@ export class App {
   }
 
   /**
-   * Gets the values on all three editors.
+   * Sets the contents of all editor panes.
    *
-   * @returns {EditorValues}
+   * @param {EditorValues} values
    */
-  public async getValues(options?: PackageJsonOptions): Promise<EditorValues> {
+  public async setEditorValues(values: Partial<EditorValues>): Promise<void> {
+    const { ElectronFiddle: fiddle } = window;
+
+    if (!fiddle) {
+      throw new Error('Fiddle not ready');
+    }
+
+    for (const name of ALL_EDITORS) {
+      const editor = fiddle.editors[name];
+      const backup = this.state.closedPanels[name];
+
+      if (typeof values[name] !== 'undefined') {
+        if (isEditorBackup(backup)) {
+          // The editor does not exist, attempt to set it on the backup.
+          // If there's a model, we'll do it on the model. Else, we'll
+          // set the value.
+
+          if (backup.model) {
+            backup.model.setValue(values[name]!);
+          } else {
+            backup.value = values[name]!;
+          }
+        } else if (editor && editor.setValue) {
+          // The editor exists, set the value directly
+          editor.setValue(values[name]!);
+        }
+      }
+    }
+  }
+
+  /**
+   * Retrieves the contents of all editor panes.
+   *
+   * @returns {EditorValues}
+   */
+  public async getEditorValues(
+    options?: PackageJsonOptions
+  ): Promise<EditorValues> {
     const { ElectronFiddle: fiddle } = window;
 
     if (!fiddle) {
       throw new Error('Fiddle not ready');
     }
 
-    const { main, html, renderer } = fiddle.editors;
     const values: EditorValues = {
-      html: html && html.getValue() ? html.getValue() : '',
-      main: main && main.getValue() ? main.getValue() : '',
-      renderer: renderer && renderer.getValue() ? renderer.getValue() : '',
+      html: getEditorValue(EditorId.html),
+      main: getEditorValue(EditorId.main),
+      preload: getEditorValue(EditorId.preload),
+      renderer: getEditorValue(EditorId.renderer)
     };
 
-    if (options && options.include !==  false) {
+    if (options && options.include !== false) {
       values.package = await getPackageJson(this.state, values, options);
     }
 
@@ -104,16 +155,18 @@ export class App {
 
     const React = await import('react');
     const { render } = await import('react-dom');
-    const { Header } = await import('./components/header');
     const { Dialogs } = await import('./components/dialogs');
-    const { Editors } = await import('./components/editors');
+    const { OutputEditorsWrapper } = await import(
+      './components/output-editors-wrapper'
+    );
+    const { Header } = await import('./components/header');
 
     const className = `${process.platform} container`;
     const app = (
       <div className={className}>
-        <Header appState={this.state} />
         <Dialogs appState={this.state} />
-        <Editors appState={this.state} />
+        <Header appState={this.state} />
+        <OutputEditorsWrapper appState={this.state} />
       </div>
     );
 
@@ -121,7 +174,9 @@ export class App {
 
     this.setupResizeListener();
 
-    // Todo: A timer here is terrible. Let's fix this
+    ipcRenderer.send(WEBCONTENTS_READY_FOR_IPC_SIGNAL);
+
+    // TODO: A timer here is terrible. Let's fix this
     // and ensure we actually do it once Editors have mounted.
     setTimeout(() => {
       this.setupUnsavedOnChangeListener();
@@ -151,7 +206,9 @@ export class App {
    * @returns {Promise<void>}
    */
   public async setupTheme(): Promise<void> {
-    const tag: HTMLStyleElement | null = document.querySelector('style#fiddle-theme');
+    const tag: HTMLStyleElement | null = document.querySelector(
+      'style#fiddle-theme'
+    );
     const theme = await getTheme(this.state.theme);
 
     if (tag && theme.css) {
@@ -175,6 +232,7 @@ export class App {
 }
 
 window.ElectronFiddle = window.ElectronFiddle || {};
-window.ElectronFiddle.contentChangeListeners = window.ElectronFiddle.contentChangeListeners || [];
+window.ElectronFiddle.contentChangeListeners =
+  window.ElectronFiddle.contentChangeListeners || [];
 window.ElectronFiddle.app = window.ElectronFiddle.app || new App();
 window.ElectronFiddle.app.setup();

src/renderer/binary.ts

@@ -4,6 +4,7 @@ import * as path from 'path';
 import { fancyImport } from '../utils/import';
 import { normalizeVersion } from '../utils/normalize-version';
 import { USER_DATA_PATH } from './constants';
+import { getOfflineTypeDefinitionPath } from './fetch-types';
 
 /**
  * The binary manager takes care of downloading Electron versions
@@ -19,31 +20,48 @@ export class BinaryManager {
    * four times before giving up if an error occurs.
    *
    * @param {string} iVersion
-   * @param {number} iteration
    * @returns {Promise<void>}
    */
-  public async remove(iVersion: string, i: number = 0): Promise<void> {
+  public async remove(iVersion: string): Promise<void> {
     const version = normalizeVersion(iVersion);
     const fs = await fancyImport<typeof fsType>('fs-extra');
+    let isDeleted = false;
 
-    try {
+    // utility to re-run removal functions upon failure
+    // due to windows filesystem lockfile jank
+    const rerunner = async (func: () => Promise<void>, counter: number = 1) => {
+      try {
+        await func();
+      } catch (error) {
+        console.warn(`Binary Manager: failed to run ${func.name} for ${version}, but failed`, error);
+        if (counter < 4) {
+          console.log(`Binary Manager: Trying again to run ${func.name}`);
+          await rerunner(func, counter + 1);
+        }
+      }
+    };
+
+    const binaryCleaner = async () => {
       if (await this.getIsDownloaded(version)) {
         // This is necessary since we're messing with .asar files inside
         // the Electron binaries. Electron, powering Fiddle, will try to
         // "correct" our calls, but we don't want that right here.
         process.noAsar = true;
-
         await fs.remove(this.getDownloadPath(version));
-
         process.noAsar = false;
-      }
-    } catch (error) {
-      console.warn(`Binary Manager: Tried to remove ${version}, but failed`, error);
 
-      if (i < 3) {
-        console.log(`Binary Manager: Trying again`);
-        return this.remove(version, i + 1);
+        isDeleted = true;
       }
+    };
+
+    const typeDefsCleaner = async () => {
+      await this.removeTypeDefsForVersion(version);
+    };
+
+    await rerunner(binaryCleaner);
+
+    if (isDeleted) {
+      await rerunner(typeDefsCleaner);
     }
   }
 
@@ -89,7 +107,7 @@ export class BinaryManager {
     } catch (error) {
       console.warn(`Failure while unzipping ${version}`, error);
 
-      // Todo: Handle this case
+      // TODO: Handle this case
     }
 
     this.state[version] = 'ready';
@@ -160,6 +178,20 @@ export class BinaryManager {
     return fs.existsSync(expectedPath);
   }
 
+  public async removeTypeDefsForVersion(version: string) {
+    const fs = await fancyImport<typeof fsType>('fs-extra');
+    const _version = normalizeVersion(version);
+    const typeDefsDir = path.dirname(getOfflineTypeDefinitionPath(_version));
+
+    if (fs.existsSync(typeDefsDir)) {
+      try {
+        await fs.remove(typeDefsDir);
+      } catch (error) {
+        throw error;
+      }
+    }
+  }
+
   /**
    * Gets the expected path for a given Electron version
    *
@@ -170,8 +202,9 @@ export class BinaryManager {
     return path.join(USER_DATA_PATH, 'electron-bin', version);
   }
 
+
   /**
-   * Unzips an electron package so that we can actaully use it.
+   * Unzips an electron package so that we can actually use it.
    *
    * @param {string} zipPath
    * @param {string} extractPath

src/renderer/bisect.ts

@@ -0,0 +1,58 @@
+import { ElectronVersion } from '../interfaces';
+
+export class Bisector {
+  public revList: Array<ElectronVersion>;
+  public minRev: number;
+  public maxRev: number;
+  private pivot: number;
+
+  constructor(revList: Array<ElectronVersion>) {
+    this.getCurrentVersion = this.getCurrentVersion.bind(this);
+    this.continue = this.continue.bind(this);
+    this.calculatePivot = this.calculatePivot.bind(this);
+
+    this.revList = revList;
+    this.minRev = 0;
+    this.maxRev = revList.length - 1;
+    this.calculatePivot();
+  }
+
+  public getCurrentVersion() {
+    return this.revList[this.pivot];
+  }
+
+  public continue(isGoodVersion: boolean) {
+    let isBisectOver = false;
+    if (this.maxRev - this.minRev <= 1) {
+      isBisectOver = true;
+    }
+
+    if (isGoodVersion) {
+      const upPivot = Math.floor((this.maxRev - this.pivot) / 2) + this.pivot;
+      this.minRev = this.pivot;
+      if (upPivot !== this.maxRev && upPivot !== this.pivot) {
+        this.pivot = upPivot;
+      } else {
+        isBisectOver = true;
+      }
+    } else {
+      const downPivot = Math.floor((this.pivot - this.minRev) / 2) + this.minRev;
+      this.maxRev = this.pivot;
+      if (downPivot !== this.minRev && downPivot !== this.pivot) {
+        this.pivot = downPivot;
+      } else {
+        isBisectOver = true;
+      }
+    }
+
+    if (isBisectOver) {
+      return [this.revList[this.minRev], this.revList[this.maxRev]];
+    } else {
+      return this.revList[this.pivot];
+    }
+  }
+
+  private calculatePivot() {
+    this.pivot = Math.floor((this.maxRev - this.minRev) / 2);
+  }
+}

src/renderer/components/commands-address-bar.tsx

@@ -4,10 +4,9 @@ import { reaction } from 'mobx';
 import { observer } from 'mobx-react';
 import * as React from 'react';
 
-import { INDEX_HTML_NAME, MAIN_JS_NAME, RENDERER_JS_NAME } from '../../shared-constants';
-import { getTitle } from '../../utils/get-title';
+import { IpcEvents } from '../../ipc-events';
 import { idFromUrl, urlFromId } from '../../utils/gist';
-import { getOctokit } from '../../utils/octokit';
+import { ipcRendererManager } from '../ipc';
 import { AppState } from '../state';
 
 export interface AddressBarProps {
@@ -16,21 +15,32 @@ export interface AddressBarProps {
 
 export interface AddressBarState {
   value: string;
+  loaders: {
+    gist: any;
+    example: any;
+  };
 }
 
 @observer
 export class AddressBar extends React.Component<AddressBarProps, AddressBarState> {
   constructor(props: AddressBarProps) {
     super(props);
-
-    this.loadFiddle = this.loadFiddle.bind(this);
     this.handleSubmit = this.handleSubmit.bind(this);
     this.handleChange = this.handleChange.bind(this);
+    this.submit = this.submit.bind(this);
 
     const { gistId } = this.props.appState;
     const value = gistId ? urlFromId(gistId) : '';
 
-    this.state = { value };
+    const { remoteLoader } = window.ElectronFiddle.app;
+
+    this.state = {
+      value,
+      loaders: {
+        gist: remoteLoader.loadFiddleFromGist.bind(remoteLoader),
+        example: remoteLoader.loadFiddleFromElectronExample.bind(remoteLoader)
+      }
+    };
   }
 
   /**
@@ -39,15 +49,20 @@ export class AddressBar extends React.Component<AddressBarProps, AddressBarState
    *
    * @param {React.SyntheticEvent<HTMLFormElement>} event
    */
-  public async handleSubmit(event: React.SyntheticEvent<HTMLFormElement>) {
+  public handleSubmit(event: React.SyntheticEvent<HTMLFormElement>) {
     event.preventDefault();
+    this.submit();
+  }
 
-    this.props.appState.gistId = idFromUrl(this.state.value) || this.state.value;
-
-    console.log('Loading');
-
+  /**
+   * Commit the address bar's value to app state and load the fiddle.
+   *
+   * @memberof AddressBar
+   */
+  public submit() {
+    const { remoteLoader } = window.ElectronFiddle.app;
     if (this.state.value) {
-      this.loadFiddle();
+      remoteLoader.fetchGistAndLoad(idFromUrl(this.state.value) || this.state.value);
     }
   }
 
@@ -55,10 +70,20 @@ export class AddressBar extends React.Component<AddressBarProps, AddressBarState
    * Once the component mounts, we'll subscribe to gistId changes
    */
   public componentDidMount() {
+    const { appState } = this.props;
+    const { loaders } = this.state;
     reaction(
-      () => this.props.appState.gistId,
+      () => appState.gistId,
       (gistId: string) => this.setState({ value: urlFromId(gistId) })
     );
+    ipcRendererManager.on(IpcEvents.LOAD_GIST_REQUEST, loaders.gist);
+    ipcRendererManager.on(IpcEvents.LOAD_ELECTRON_EXAMPLE_REQUEST, loaders.example);
+  }
+
+  public componentWillUnmount() {
+    const { loaders } = this.state;
+    ipcRendererManager.removeListener(IpcEvents.LOAD_GIST_REQUEST, loaders.gist);
+    ipcRendererManager.removeListener(IpcEvents.LOAD_ELECTRON_EXAMPLE_REQUEST, loaders.example);
   }
 
   /**
@@ -70,69 +95,36 @@ export class AddressBar extends React.Component<AddressBarProps, AddressBarState
     this.setState({ value: event.target.value });
   }
 
-  /**
-   * Load a fiddle
-   *
-   * @returns {Promise<boolean>}
-   * @memberof AddressBar
-   */
-  public async loadFiddle(): Promise<boolean> {
-    const { appState } = this.props;
-
-    try {
-      const octo = await getOctokit();
-      const gist = await octo.gists.get({
-        gist_id: appState.gistId
-      });
-
-      this.props.appState.setWarningDialogTexts({
-        label: 'Loading the fiddle will replace your current unsaved changes. Do you want to discard them?'
-      });
-
-      await window.ElectronFiddle.app.setValues({
-        html: gist.data.files[INDEX_HTML_NAME].content,
-        main: gist.data.files[MAIN_JS_NAME].content,
-        renderer: gist.data.files[RENDERER_JS_NAME].content,
-      });
-
-      document.title = getTitle(appState);
-      appState.localPath = null;
-    } catch (error) {
-      console.warn(`Loading Fiddle failed`, error);
-      return false;
-    }
-
-    return true;
-  }
-
   public renderLoadButton(isValueCorrect: boolean): JSX.Element {
     return (
       <Button
         disabled={!isValueCorrect}
         icon='cloud-download'
         text='Load Fiddle'
-        onClick={this.loadFiddle}
+        onClick={this.submit}
       />
     );
   }
 
   public render() {
-    const { isUnsaved } = this.props.appState;
+    const { isUnsaved, isPublishing } = this.props.appState;
     const { value } = this.state;
     const isCorrect = /https:\/\/gist\.github\.com\/(.+)$/.test(value);
     const className = classnames('address-bar', isUnsaved, { empty: !value });
 
     return (
       <form className={className} onSubmit={this.handleSubmit}>
-        <InputGroup
-          key='addressbar'
-          leftIcon='geosearch'
-          intent={isCorrect || !value ? undefined : Intent.DANGER}
-          onChange={this.handleChange}
-          placeholder='https://gist.github.com/...'
-          value={value}
-          rightElement={this.renderLoadButton(isCorrect)}
-        />
+        <fieldset disabled={isPublishing}>
+          <InputGroup
+            key='addressbar'
+            leftIcon='geosearch'
+            intent={isCorrect || !value ? undefined : Intent.DANGER}
+            onChange={this.handleChange}
+            placeholder='https://gist.github.com/...'
+            value={value}
+            rightElement={this.renderLoadButton(isCorrect)}
+          />
+        </fieldset>
       </form>
     );
   }

src/renderer/components/commands-bisect.tsx

@@ -0,0 +1,80 @@
+import { Button } from '@blueprintjs/core';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { GenericDialogType } from '../../../src/interfaces';
+import { AppState } from '../state';
+
+interface BisectHandlerProps {
+  appState: AppState;
+}
+
+@observer
+export class BisectHandler extends React.Component<BisectHandlerProps> {
+  constructor(props: BisectHandlerProps) {
+    super(props);
+
+    this.continueBisect = this.continueBisect.bind(this);
+    this.terminateBisect = this.terminateBisect.bind(this);
+  }
+
+  public continueBisect(isGood: boolean) {
+    const { appState } = this.props;
+    const response = appState.Bisector!.continue(isGood);
+
+    if (Array.isArray(response)) {
+      this.terminateBisect();
+
+      const [minRev, maxRev] = response;
+      const [minVer, maxVer] = [minRev.version, maxRev.version];
+      const message = `Check between versions ${minVer} and ${maxVer}.`;
+
+      appState.pushOutput(`[BISECT] Complete: ${message}`);
+      appState.setGenericDialogOptions({
+        type: GenericDialogType.success,
+        label: `Bisect complete. ${message}`,
+        cancel: undefined
+      });
+      appState.isGenericDialogShowing = true;
+    } else {
+      appState.setVersion(response.version);
+    }
+  }
+
+  public terminateBisect() {
+    const { appState } = this.props;
+    appState.Bisector = undefined;
+  }
+
+  public render() {
+    const { appState } = this.props;
+    if (!!appState.Bisector) {
+      return (
+        <>
+          <Button
+            icon={'thumbs-up'}
+            onClick={() => this.continueBisect(true)}
+          />
+          <Button
+            icon={'thumbs-down'}
+            onClick={() => this.continueBisect(false)}
+          />
+          <Button
+            icon={'cross'}
+            onClick={this.terminateBisect}
+          >
+            Cancel Bisect
+          </Button>
+        </>
+      );
+    } else {
+      return (
+        <Button
+          icon='git-branch'
+          text='Bisect'
+          onClick={appState.toggleBisectDialog}
+        />
+      );
+    }
+  }
+}

src/renderer/components/commands-editors.tsx

@@ -0,0 +1,100 @@
+import { Button, Menu, MenuItem, Popover, Position } from '@blueprintjs/core';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { ALL_EDITORS, MosaicId, PanelId } from '../../interfaces';
+import { getVisibleMosaics } from '../../utils/editors-mosaic-arrangement';
+import { AppState } from '../state';
+import { TITLE_MAP } from './editors';
+
+export interface EditorDropdownState {
+  value: string;
+}
+
+export interface EditorDropdownProps {
+  appState: AppState;
+}
+
+/**
+ * A dropdown allowing users to toggle the various editors
+ *
+ * @class EditorDropdown
+ * @extends {React.Component<EditorDropdownProps, EditorDropdownState>}
+ */
+@observer
+export class EditorDropdown extends React.Component<EditorDropdownProps, EditorDropdownState> {
+  constructor(props: EditorDropdownProps) {
+    super(props);
+
+    this.onItemClick = this.onItemClick.bind(this);
+  }
+
+  public render() {
+    return (
+      <>
+        <Popover content={this.renderMenu()} position={Position.BOTTOM}>
+          <Button icon='applications' text='Editors' />
+        </Popover>
+        {this.renderDocsDemos()}
+      </>
+    );
+  }
+
+  public renderDocsDemos() {
+    if (!process.env.FIDDLE_DOCS_DEMOS) {
+      return null;
+    }
+
+    return (
+      <Button
+        icon='help'
+        text='Docs & Demos'
+        id={PanelId.docsDemo}
+        onClick={this.onItemClick}
+        active={!this.props.appState.closedPanels.docsDemo}
+      />
+    );
+  }
+
+  public renderMenu() {
+    return (
+      <Menu>
+        {...this.renderMenuItems()}
+      </Menu>
+    );
+  }
+
+  public renderMenuItems() {
+    const { appState } = this.props;
+    const result: Array<JSX.Element> = [];
+    const visibleMosaics = getVisibleMosaics(appState.mosaicArrangement);
+
+    for (const id of ALL_EDITORS) {
+      result.push(
+        <MenuItem
+          icon={visibleMosaics.includes(id) ? 'eye-open' : 'eye-off'}
+          key={id}
+          text={TITLE_MAP[id]}
+          id={id}
+          onClick={this.onItemClick}
+        />
+      );
+    }
+
+    return result;
+  }
+
+  public onItemClick(event: React.MouseEvent) {
+    const { id } = event.currentTarget;
+    const { appState } = this.props;
+    const visibleMosaics = getVisibleMosaics(appState.mosaicArrangement);
+
+    if (visibleMosaics.includes(id as MosaicId)) {
+      console.log(`EditorDropdown: Closing ${id}`);
+      appState.hideAndBackupMosaic(id as MosaicId);
+    } else {
+      console.log(`EditorDropdown: Opening ${id}`);
+      appState.showMosaic(id as MosaicId);
+    }
+  }
+}

src/renderer/components/commands-publish-button.tsx

@@ -4,7 +4,7 @@ import * as React from 'react';
 
 import { when } from 'mobx';
 import { IpcEvents } from '../../ipc-events';
-import { INDEX_HTML_NAME, MAIN_JS_NAME, RENDERER_JS_NAME } from '../../shared-constants';
+import { INDEX_HTML_NAME, MAIN_JS_NAME, PRELOAD_JS_NAME, RENDERER_JS_NAME } from '../../shared-constants';
 import { getOctokit } from '../../utils/octokit';
 import { ipcRendererManager } from '../ipc';
 import { AppState } from '../state';
@@ -13,10 +13,6 @@ export interface PublishButtonProps {
   appState: AppState;
 }
 
-export interface PublishButtonState {
-  isPublishing: boolean;
-}
-
 /**
  * The "publish" button takes care of logging you in.
  *
@@ -25,11 +21,9 @@ export interface PublishButtonState {
  * @extends {React.Component<PublishButtonProps, PublishButtonState>}
  */
 @observer
-export class PublishButton extends React.Component<PublishButtonProps, PublishButtonState> {
+export class PublishButton extends React.Component<PublishButtonProps> {
   constructor(props: PublishButtonProps) {
     super(props);
-
-    this.state = { isPublishing: false };
     this.handleClick = this.handleClick.bind(this);
     this.publishFiddle = this.publishFiddle.bind(this);
     this.setPrivate = this.setPrivate.bind(this);
@@ -71,17 +65,13 @@ export class PublishButton extends React.Component<PublishButtonProps, PublishBu
    * and update all related properties in the app state.
    */
   public async publishFiddle(): Promise<void> {
-    this.setState({ isPublishing: true });
-
-    const octo = await getOctokit();
-    octo.authenticate({
-      type: 'token',
-      token: this.props.appState.gitHubToken!
-    });
+    const { appState } = this.props;
+    appState.isPublishing = true;
 
+    const octo = await getOctokit(this.props.appState);
     const { gitHubPublishAsPublic } = this.props.appState;
     const options = { includeDependencies: true, includeElectron: true };
-    const values = await window.ElectronFiddle.app.getValues(options);
+    const values = await window.ElectronFiddle.app.getEditorValues(options);
 
     try {
       const gist = await octo.gists.create({
@@ -97,10 +87,13 @@ export class PublishButton extends React.Component<PublishButtonProps, PublishBu
           [RENDERER_JS_NAME]: {
             content: values.renderer || '// Empty',
           },
+          [PRELOAD_JS_NAME]: {
+            content: values.preload || '// Empty',
+          },
         },
       } as any); // Note: GitHub messed up, GistsCreateParamsFiles is an incorrect interface
 
-      this.props.appState.gistId = gist.data.id;
+      appState.gistId = gist.data.id;
 
       console.log(`Publish Button: Publishing done`, { gist });
     } catch (error) {
@@ -114,7 +107,7 @@ export class PublishButton extends React.Component<PublishButtonProps, PublishBu
       ipcRendererManager.send(IpcEvents.SHOW_WARNING_DIALOG, messageBoxOptions);
     }
 
-    this.setState({ isPublishing: false });
+    appState.isPublishing = false;
   }
 
   /**
@@ -137,7 +130,7 @@ export class PublishButton extends React.Component<PublishButtonProps, PublishBu
 
   public render() {
     const { gitHubPublishAsPublic } = this.props.appState;
-    const { isPublishing } = this.state;
+    const { isPublishing } = this.props.appState;
 
     const privacyIcon = gitHubPublishAsPublic ? 'unlock' : 'lock';
     const privacyMenu = (
@@ -158,24 +151,24 @@ export class PublishButton extends React.Component<PublishButtonProps, PublishBu
     );
 
     return (
-      <ButtonGroup className='button-publish'>
-        <Popover
-          content={privacyMenu}
-          position={Position.BOTTOM}
-          disabled={isPublishing}
-        >
-          <Button
-            icon={privacyIcon}
-          />
-        </Popover>
-        <Button
-          onClick={this.handleClick}
-          loading={isPublishing}
-          disabled={isPublishing}
-          icon='upload'
-          text={isPublishing ? 'Publishing...' : 'Publish'}
-        />
-      </ButtonGroup>
+      <fieldset disabled={isPublishing}>
+        <ButtonGroup className='button-publish'>
+            <Popover
+              content={privacyMenu}
+              position={Position.BOTTOM}
+            >
+              <Button
+                icon={privacyIcon}
+              />
+            </Popover>
+            <Button
+              onClick={this.handleClick}
+              loading={isPublishing}
+              icon='upload'
+              text={isPublishing ? 'Publishing...' : 'Publish'}
+            />
+        </ButtonGroup>
+      </fieldset>
     );
   }
 

src/renderer/components/commands-runner.tsx

@@ -48,6 +48,6 @@ export class Runner extends React.Component<RunnerProps, RunnerState> {
       props.icon = <Spinner size={16} />;
     }
 
-    return <Button {...props} />;
+    return <Button {...props} type={undefined} />;
   }
 }

src/renderer/components/commands-version-chooser.tsx

@@ -1,95 +1,9 @@
-import { Button, MenuItem } from '@blueprintjs/core';
-import { ItemPredicate, ItemRenderer, Select } from '@blueprintjs/select';
+import { ButtonGroup } from '@blueprintjs/core';
 import { observer } from 'mobx-react';
 import * as React from 'react';
 
-import { ElectronVersion, ElectronVersionSource, ElectronVersionState } from '../../interfaces';
-import { highlightText } from '../../utils/highlight-text';
-import { sortedElectronMap } from '../../utils/sorted-electron-map';
 import { AppState } from '../state';
-import { getReleaseChannel } from '../versions';
-
-const ElectronVersionSelect = Select.ofType<ElectronVersion>();
-
-/**
- * Helper method: Returns the <Select /> label for an Electron
- * version.
- *
- * @param {ElectronVersion} { source, state }
- * @returns {string}
- */
-export function getItemLabel({ source, state, name }: ElectronVersion): string {
-  let label = '';
-
-  if (source === ElectronVersionSource.local) {
-    label = name || 'Local';
-  } else {
-    if (state === ElectronVersionState.unknown) {
-      label = `Not downloaded`;
-    } else if (state === ElectronVersionState.ready) {
-      label = `Downloaded`;
-    } else if (state === ElectronVersionState.downloading) {
-      label = `Downloading`;
-    }
-  }
-
-  return label;
-}
-
-/**
- * Helper method: Returns the <Select /> icon for an Electron
- * version.
- *
- * @param {ElectronVersion} { state }
- * @returns
- */
-export function getItemIcon({ state }: ElectronVersion) {
-  return state === 'ready'
-    ? 'saved'
-    : state === 'downloading' ? 'cloud-download' : 'cloud';
-}
-
-/**
- * Helper method: Returns the <Select /> predicate for an Electron
- * version.
- *
- * @param {string} query
- * @param {ElectronVersion} { version }
- * @returns
- */
-export const filterItem: ItemPredicate<ElectronVersion> = (query, { version }) => {
-  return version.toLowerCase().includes(query.toLowerCase());
-};
-
-/**
- * Helper method: Returns the <Select /> <MenuItem /> for Electron
- * versions.
- *
- * @param {ElectronVersion} item
- * @param {IItemRendererProps} { handleClick, modifiers, query }
- * @returns
- */
-export const renderItem: ItemRenderer<ElectronVersion> = (item, { handleClick, modifiers, query }) => {
-  if (!modifiers.matchesPredicate) {
-      return null;
-  }
-
-  return (
-    <MenuItem
-      active={modifiers.active}
-      disabled={modifiers.disabled}
-      text={highlightText(item.version, query)}
-      key={item.version}
-      onClick={handleClick}
-      label={getItemLabel(item)}
-      icon={getItemIcon(item)}
-    />
-  );
-};
-
-export interface VersionChooserState {
-  value: string;
-}
+import { VersionSelect } from './version-select';
 
 export interface VersionChooserProps {
   appState: AppState;
@@ -98,54 +12,18 @@ export interface VersionChooserProps {
 /**
  * A dropdown allowing the selection of Electron versions. The actual
  * download is managed in the state.
- *
- * @class VersionChooser
- * @extends {React.Component<VersionChooserProps, VersionChooserState>}
  */
-@observer
-export class VersionChooser extends React.Component<VersionChooserProps, VersionChooserState> {
-  constructor(props: VersionChooserProps) {
-    super(props);
+export const VersionChooser = observer((props: VersionChooserProps) => {
+  const { currentElectronVersion, Bisector, setVersion } = props.appState;
 
-    this.onItemSelect = this.onItemSelect.bind(this);
-  }
-
-  /**
-   * Handle change, which usually means that we'd like update
-   * the selection version.
-   *
-   * @param {React.ChangeEvent<HTMLSelectElement>} event
-   */
-  public onItemSelect({ version }: ElectronVersion) {
-    this.props.appState.setVersion(version);
-  }
-
-  public getItems(): Array<ElectronVersion> {
-    const { versions, versionsToShow } = this.props.appState;
-
-    return sortedElectronMap<ElectronVersion>(versions, (_key, item) => item)
-      .filter((item) => !!item && versionsToShow.includes(getReleaseChannel(item)));
-  }
-
-  public render() {
-    const { currentElectronVersion } = this.props.appState;
-    const { version } = currentElectronVersion;
-
-    return (
-      <ElectronVersionSelect
-        filterable={true}
-        items={this.getItems()}
-        itemRenderer={renderItem}
-        itemPredicate={filterItem}
-        onItemSelect={this.onItemSelect}
-        noResults={<MenuItem disabled={true} text='No results.' />}
-      >
-        <Button
-          className='version-chooser'
-          text={`Electron v${version}`}
-          icon={getItemIcon(currentElectronVersion)}
-        />
-      </ElectronVersionSelect>
-    );
-  }
-}
+  return (
+    <ButtonGroup>
+      <VersionSelect
+        appState={props.appState}
+        onVersionSelect={({ version }) => setVersion(version)}
+        currentVersion={currentElectronVersion}
+        disabled={!!Bisector}
+      />
+    </ButtonGroup>
+  );
+});

src/renderer/components/commands.tsx

@@ -4,6 +4,8 @@ import * as React from 'react';
 
 import { AppState } from '../state';
 import { AddressBar } from './commands-address-bar';
+import { BisectHandler } from './commands-bisect';
+import { EditorDropdown } from './commands-editors';
 import { PublishButton } from './commands-publish-button';
 import { Runner } from './commands-runner';
 import { VersionChooser } from './commands-version-chooser';
@@ -27,6 +29,7 @@ export class Commands extends React.Component<CommandsProps, {}> {
 
   public render() {
     const { appState } = this.props;
+    const { isBisectCommandShowing: isBisectCommandShowing } = appState;
 
     return (
       <div className='commands'>
@@ -35,6 +38,15 @@ export class Commands extends React.Component<CommandsProps, {}> {
             <VersionChooser appState={appState} />
             <Runner appState={appState} />
           </ControlGroup>
+          {
+            // tslint:disable-next-line jsx-no-multiline-js
+            isBisectCommandShowing &&
+            (
+              <ControlGroup fill={true} vertical={false}>
+                <BisectHandler appState={appState} />
+              </ControlGroup>
+            )
+          }
           <ControlGroup fill={true} vertical={false}>
             <Button
               active={appState.isConsoleShowing}
@@ -42,6 +54,7 @@ export class Commands extends React.Component<CommandsProps, {}> {
               text='Console'
               onClick={appState.toggleConsole}
             />
+            <EditorDropdown appState={appState} />
           </ControlGroup>
         </div>
         <div>

src/renderer/components/dialog-add-theme.tsx

@@ -0,0 +1,164 @@
+import { Button, Dialog, FileInput } from '@blueprintjs/core';
+import { shell } from 'electron';
+import * as fsType from 'fs-extra';
+import { observer } from 'mobx-react';
+import * as MonacoType from 'monaco-editor';
+import * as path from 'path';
+import * as React from 'react';
+import { getTheme, THEMES_PATH } from '../themes';
+
+import { GenericDialogType } from '../../../src/interfaces';
+import { AppState } from '../state';
+import { defaultDark, LoadedFiddleTheme } from '../themes-defaults';
+
+export interface AddThemeDialogProps {
+  appState: AppState;
+}
+
+export interface AddThemeDialogState {
+  file?: File;
+}
+
+/**
+ * The "add monaco theme" dialog allows users to add custom editor themes.
+ *
+ * @class AddThemeDialog
+ * @extends {React.Component<AddThemeDialogProps, AddThemeDialogState>}
+ */
+@observer
+export class AddThemeDialog extends React.Component<AddThemeDialogProps, AddThemeDialogState> {
+  public resetState = { file: undefined };
+
+  constructor(props: AddThemeDialogProps) {
+    super(props);
+    this.state = this.resetState;
+
+    this.onSubmit = this.onSubmit.bind(this);
+    this.onClose = this.onClose.bind(this);
+    this.onChangeFile = this.onChangeFile.bind(this);
+    this.reset = this.reset.bind(this);
+  }
+
+  /**
+   * Handles a change of the file input
+   *
+   * @param {React.ChangeEvent<HTMLInputElement>} event
+   */
+  public async onChangeFile(event: React.FormEvent<HTMLInputElement>) {
+    const { files } = event.target as any;
+    const file = files && files[0] ? files[0] : undefined;
+
+    this.setState({ file });
+  }
+
+  /**
+   * Handles the submission of the dialog
+   *
+   * @returns {Promise<void>}
+   */
+  public async onSubmit(): Promise<void> {
+    const { file } = this.state;
+    const defaultTheme = !!this.props.appState.theme ? await getTheme(this.props.appState.theme) : defaultDark;
+    if (!file) return;
+
+    try {
+      const editor = fsType.readJSONSync(file.path);
+      if (!editor.base && !editor.rules) throw Error('File does not match specifications'); // has to have these attributes
+      defaultTheme.editor = editor as Partial<MonacoType.editor.IStandaloneThemeData>;
+      const newTheme = defaultTheme;
+      const name = editor.name ? editor.name : file.name;
+      await this.createNewThemeFromMonaco(name, newTheme);
+    } catch (error) {
+      this.props.appState.setGenericDialogOptions({
+        type: GenericDialogType.warning,
+        label: `Error: ${error}, please pick a different file.`
+      });
+      this.props.appState.isGenericDialogShowing = true;
+      return;
+    }
+
+    this.onClose();
+    return;
+  }
+
+  public async createNewThemeFromMonaco(name: string, newTheme: LoadedFiddleTheme): Promise<boolean> {
+      if (!name) return false;
+      const themePath = path.join(THEMES_PATH, `${name}`);
+
+      await fsType.outputJSON(themePath, {
+        ...newTheme,
+        name,
+      }, {spaces: 2});
+
+      this.props.appState.setTheme(themePath);
+      shell.showItemInFolder(themePath);
+      return true;
+  }
+
+  get buttons() {
+    const canSubmit = !!this.state.file;
+
+    return [
+      (
+        <Button
+          icon='add'
+          key='submit'
+          disabled={!canSubmit}
+          onClick={this.onSubmit}
+          text='Add'
+        />
+      ), (
+        <Button
+          icon='cross'
+          key='cancel'
+          onClick={this.onClose}
+          text='Cancel'
+        />
+      )
+    ];
+  }
+
+  public onClose() {
+    this.props.appState.isThemeDialogShowing = false;
+    this.reset();
+  }
+
+  public render() {
+    const { isThemeDialogShowing } = this.props.appState;
+    const inputProps = { accept: '.json' };
+    const { file } = this.state;
+
+    const text = file && file.path ? file.path : `Select the Monaco file...`;
+    return (
+      <Dialog
+        isOpen={isThemeDialogShowing}
+        onClose={this.onClose}
+        title='Add theme'
+        className='dialog-add-version'
+      >
+        <div className='bp3-dialog-body'>
+          <FileInput
+            onInputChange={this.onChangeFile}
+            inputProps={inputProps as any}
+            text={text}
+          />
+          <br />
+        </div>
+        <div className='bp3-dialog-footer'>
+          <div className='bp3-dialog-footer-actions'>
+            {this.buttons}
+          </div>
+        </div>
+      </Dialog>
+    );
+  }
+
+  /**
+   * Reset this component's state
+   */
+  private reset(): void {
+    this.setState(this.resetState);
+    return;
+  }
+
+}

src/renderer/components/dialog-add-version.tsx

@@ -6,7 +6,9 @@ import * as React from 'react';
 import * as semver from 'semver';
 
 import { NpmVersion } from '../../interfaces';
+import { IpcEvents } from '../../ipc-events';
 import { getElectronNameForPlatform } from '../../utils/electron-name';
+import { ipcRendererManager } from '../ipc';
 import { AppState } from '../state';
 
 export interface AddVersionDialogProps {
@@ -16,7 +18,7 @@ export interface AddVersionDialogProps {
 export interface AddVersionDialogState {
   isValidElectron: boolean;
   isValidVersion: boolean;
-  file?: File;
+  folderPath?: string;
   version: string;
 }
 
@@ -39,8 +41,15 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
 
     this.onSubmit = this.onSubmit.bind(this);
     this.onClose = this.onClose.bind(this);
-    this.onChangeFile = this.onChangeFile.bind(this);
     this.onChangeVersion = this.onChangeVersion.bind(this);
+
+    ipcRendererManager.on(IpcEvents.LOAD_LOCAL_VERSION_FOLDER, (_event, [file]) => {
+      this.setFolderPath(file);
+    });
+  }
+
+  public componentWillUnmount() {
+    ipcRendererManager.removeAllListeners(IpcEvents.LOAD_LOCAL_VERSION_FOLDER);
   }
 
   /**
@@ -48,16 +57,11 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
    *
    * @param {React.ChangeEvent<HTMLInputElement>} event
    */
-  public async onChangeFile(event: React.FormEvent<HTMLInputElement>) {
-    const { files } = event.target as any;
+  public async setFolderPath(folderPath: string) {
     const { binaryManager } = this.props.appState;
-    const file = files && files[0] ? files[0] : undefined;
+    const isValidElectron = !!await binaryManager.getIsDownloaded('custom', folderPath);
 
-    const isValidElectron = !!(file
-      && file.path
-      && await binaryManager.getIsDownloaded('custom', file.path));
-
-    this.setState({ file, isValidElectron });
+    this.setState({ folderPath, isValidElectron });
   }
 
   public onChangeVersion(event: React.ChangeEvent<HTMLInputElement>) {
@@ -67,7 +71,7 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
     this.setState({
       version,
       isValidVersion,
-     });
+    });
   }
 
   /**
@@ -76,18 +80,18 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
    * @returns {Promise<void>}
    */
   public async onSubmit(): Promise<void> {
-    const { file, version } = this.state;
+    const { folderPath, version } = this.state;
 
-    if (!file) return;
+    if (!folderPath) return;
 
-    const name = file.path
+    const name = folderPath
       .slice(-20)
       .split(path.sep)
       .slice(1)
       .join(path.sep);
 
     const toAdd: NpmVersion = {
-      localPath: file.path,
+      localPath: folderPath,
       version,
       name
     };
@@ -129,12 +133,16 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
 
   public render() {
     const { isAddVersionDialogShowing } = this.props.appState;
-    const inputProps = { webkitdirectory: 'true' };
-    const { file } = this.state;
+    const inputProps = {
+      onClick: (e: React.MouseEvent<HTMLInputElement, MouseEvent>) => {
+        e.preventDefault();
+        ipcRendererManager.send(IpcEvents.SHOW_LOCAL_VERSION_FOLDER_DIALOG);
+      }
+    };
+    const { folderPath } = this.state;
 
-    const text = file && file.path
-      ? file.path
-      : `Select the folder containing ${getElectronNameForPlatform()}...`;
+    const text = folderPath ||
+      `Select the folder containing ${getElectronNameForPlatform()}...`;
 
     return (
       <Dialog
@@ -145,7 +153,6 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
       >
         <div className='bp3-dialog-body'>
           <FileInput
-            onInputChange={this.onChangeFile}
             id='custom-electron-version'
             inputProps={inputProps as any}
             text={text}
@@ -163,9 +170,9 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
   }
 
   private renderPath(): JSX.Element | null {
-    const { file, isValidElectron } = this.state;
+    const { folderPath, isValidElectron } = this.state;
 
-    if (!file || !file.path) return null;
+    if (!folderPath) return null;
 
     const info = isValidElectron
       ? `We found an ${getElectronNameForPlatform()} in this folder.`
@@ -208,7 +215,7 @@ export class AddVersionDialog extends React.Component<AddVersionDialogProps, Add
       isValidElectron: false,
       isValidVersion: false,
       version: '',
-      file: undefined
+      folderPath: undefined
     });
   }
 }

src/renderer/components/dialog-bisect.tsx

@@ -0,0 +1,236 @@
+import { Button, ButtonGroup, Callout, Dialog, Label } from '@blueprintjs/core';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { ElectronVersion } from '../../interfaces';
+import { Bisector } from '../bisect';
+import { AppState } from '../state';
+import { VersionSelect } from './version-select';
+
+export interface BisectDialogProps {
+  appState: AppState;
+}
+
+export interface BisectDialogState {
+  startIndex: number;
+  endIndex: number;
+  allVersions: Array<ElectronVersion>;
+  showHelp?: boolean;
+}
+
+/**
+ * The "add version" dialog allows users to add custom builds of Electron.
+ *
+ * @class BisectDialog
+ * @extends {React.Component<BisectDialogProps, BisectDialogState>}
+ */
+@observer
+export class BisectDialog extends React.Component<BisectDialogProps, BisectDialogState> {
+  constructor(props: BisectDialogProps) {
+    super(props);
+
+    this.onSubmit = this.onSubmit.bind(this);
+    this.onClose = this.onClose.bind(this);
+    this.onBeginSelect = this.onBeginSelect.bind(this);
+    this.onEndSelect = this.onEndSelect.bind(this);
+    this.showHelp = this.showHelp.bind(this);
+    this.isEarliestItemDisabled = this.isEarliestItemDisabled.bind(this);
+    this.isLatestItemDisabled = this.isLatestItemDisabled.bind(this);
+
+    this.state = {
+      allVersions: this.props.appState.versionsToShow,
+      startIndex: 10,
+      endIndex: 0
+    };
+  }
+
+  public onBeginSelect(version: ElectronVersion) {
+    this.setState({ startIndex: this.state.allVersions.indexOf(version) });
+  }
+
+  public onEndSelect(version: ElectronVersion) {
+    this.setState({ endIndex: this.state.allVersions.indexOf(version) });
+  }
+
+  /**
+   * Handles the submission of the dialog
+   *
+   * @returns {Promise<void>}
+   */
+  public async onSubmit(): Promise<void> {
+    const { endIndex, startIndex, allVersions } = this.state;
+    const { appState } = this.props;
+
+    if (endIndex === undefined || startIndex === undefined) {
+      return;
+    }
+
+    const bisectRange = allVersions
+      .slice(endIndex, startIndex + 1);
+
+    appState.Bisector = new Bisector(bisectRange);
+    const initialBisectPivot = appState.Bisector.getCurrentVersion().version;
+    appState.setVersion(initialBisectPivot);
+    this.onClose();
+  }
+
+  /**
+   * Closes the dialog
+   */
+  public onClose() {
+    this.props.appState.isBisectDialogShowing = false;
+  }
+
+  /**
+   * Shows the additional help
+   */
+  public showHelp() {
+    this.setState({ showHelp: true });
+  }
+
+  /**
+   * Can we get this show on the road?
+   */
+  get canSubmit(): boolean {
+    return this.state.startIndex > this.state.endIndex;
+  }
+
+  /**
+   * Renders the buttons
+   */
+  get buttons() {
+    return [
+      (
+        <Button
+          icon='play'
+          key='submit'
+          disabled={!this.canSubmit}
+          onClick={this.onSubmit}
+          text='Begin'
+        />
+      ), (
+        <Button
+          icon='cross'
+          key='cancel'
+          onClick={this.onClose}
+          text='Cancel'
+        />
+      )
+    ];
+  }
+
+  /**
+   * Renders the help
+   */
+  get help() {
+    let moreHelp = (
+      <Button
+        icon='help'
+        text='Show help'
+        onClick={this.showHelp}
+      />
+    );
+
+    if (this.state.showHelp) {
+      moreHelp = (
+        <>
+          <p>
+            First, write a fiddle that reproduces a bug or an issue. Then, select the earliest version to
+            start your search with. Typically, that's the "last known good" version that did not have the bug.
+            Then, select that latest version to end the search with, usually the "first known bad" version.
+          </p>
+          <p>
+            Once you begin your bisect, Fiddle will run your fiddle with a number of Electron versions, closing
+            in on the version that introduced the bug. Once completed, you will know which Electron version
+            introduced your issue.
+          </p>
+        </>
+      );
+    }
+
+    return (
+      <Callout style={{ marginTop: 0, marginBottom: '1rem' }}>
+        <p>
+          A "bisect" is a popular method <a href='https://git-scm.com/docs/git-bisect' target='_blank'>
+          borrowed from <code>git</code></a> for learning which version of Electron introduced a bug. This
+          tool helps you perform a bisect.
+        </p>
+        {moreHelp}
+      </Callout>
+    );
+  }
+
+  public render() {
+    const { isBisectDialogShowing } = this.props.appState;
+    const { startIndex, endIndex, allVersions } = this.state;
+
+    return (
+      <Dialog
+        isOpen={isBisectDialogShowing}
+        onClose={this.onClose}
+        title='Start a bisect session'
+        className='dialog-add-version'
+      >
+        <div className='bp3-dialog-body'>
+          {this.help}
+          <Label>
+            Earliest Version (Last "known good" version)
+            <ButtonGroup fill={true}>
+              <VersionSelect
+                currentVersion={allVersions[startIndex]}
+                appState={this.props.appState}
+                onVersionSelect={this.onBeginSelect}
+                itemDisabled={this.isEarliestItemDisabled}
+              />
+            </ButtonGroup>
+          </Label>
+          <Label>
+            Latest Version (First "known bad" version)
+            <ButtonGroup fill={true}>
+              <VersionSelect
+                currentVersion={allVersions[endIndex]}
+                appState={this.props.appState}
+                onVersionSelect={this.onEndSelect}
+                itemDisabled={this.isLatestItemDisabled}
+              />
+            </ButtonGroup>
+          </Label>
+        </div>
+        <div className='bp3-dialog-footer'>
+          <div className='bp3-dialog-footer-actions'>
+            {this.buttons}
+          </div>
+        </div>
+      </Dialog>
+    );
+  }
+
+  /**
+   * Should an item in the "earliest version" dropdown be disabled?
+   *
+   * @param {ElectronVersion} version
+   * @returns {boolean}
+   */
+  public isEarliestItemDisabled(version: ElectronVersion): boolean {
+    const { allVersions, endIndex } = this.state;
+
+    // In the array, "newer" versions will have a lower index.
+    // 0: 5.0.0
+    // 1: 4.0.0
+    // 2: 3.0.0
+    // ...
+    return allVersions.indexOf(version) < endIndex + 1;
+  }
+
+  /**
+   * Should an item in the "latest version" dropdown be disabled?
+   *
+   * @param {ElectronVersion} version
+   * @returns {boolean}
+   */
+  public isLatestItemDisabled(version: ElectronVersion): boolean {
+    const { allVersions, startIndex } = this.state;
+
+    return allVersions.indexOf(version) > startIndex - 1;
+  }
+}

src/renderer/components/dialog-generic.tsx

@@ -0,0 +1,73 @@
+
+import { Alert, IconName, Intent} from '@blueprintjs/core';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { GenericDialogType } from '../../../src/interfaces';
+import { AppState } from '../state';
+
+export interface GenericDialogProps {
+  appState: AppState;
+}
+
+export interface GenericDialogState {
+}
+
+/**
+ * The token dialog prompts the user to either continue or cancel the operation.
+ *
+ * @export
+ * @class GenericDialog
+ * @extends {React.Component<GenericDialogProps, GenericDialogState>}
+ */
+@observer
+export class GenericDialog extends React.Component<GenericDialogProps, GenericDialogState> {
+  constructor(props: GenericDialogProps) {
+    super(props);
+
+    this.onClose = this.onClose.bind(this);
+  }
+
+  public onClose(result: boolean) {
+    this.props.appState.genericDialogLastResult = result;
+    this.props.appState.toggleGenericDialog();
+  }
+
+  public render() {
+    const { isGenericDialogShowing, genericDialogOptions } = this.props.appState;
+    const {type, ok, cancel, label} = genericDialogOptions;
+
+    let intent: Intent;
+    let icon: IconName;
+    switch (type) {
+      case GenericDialogType.warning:
+        intent = Intent.DANGER;
+        icon = 'warning-sign';
+        break;
+      case GenericDialogType.confirm:
+        intent = Intent.PRIMARY;
+        icon = 'help';
+        break;
+      case GenericDialogType.success:
+        intent = Intent.SUCCESS;
+        icon = 'info-sign';
+        break;
+      default:
+        intent = Intent.NONE;
+        icon = 'help';
+        break;
+    }
+    return (
+      <Alert
+        isOpen={isGenericDialogShowing}
+        onClose={this.onClose}
+        icon={icon}
+        confirmButtonText={ok}
+        cancelButtonText={cancel}
+        intent={intent}
+      >
+        <p>{label}</p>
+      </Alert>
+    );
+  }
+}

src/renderer/components/dialog-token.tsx

@@ -56,28 +56,23 @@ export class TokenDialog extends React.Component<TokenDialogProps, TokenDialogSt
   public async onSubmitToken(): Promise<void> {
     if (!this.state.tokenInput) return;
     this.setState({ verifying: true });
+    this.props.appState.gitHubToken = this.state.tokenInput;
 
-    const octo = await getOctokit();
-    octo.authenticate({
-      type: 'token',
-      token: this.state.tokenInput,
-    });
+    const octo = await getOctokit(this.props.appState);
 
     try {
-      const { data } = await octo.users.get({});
+      const { data } = await octo.users.getAuthenticated();
       this.props.appState.gitHubAvatarUrl = data.avatar_url;
       this.props.appState.gitHubLogin = data.login;
       this.props.appState.gitHubName = data.name;
+      this.setState({ verifying: false, error: false });
     } catch (error) {
       console.warn(`Authenticating against GitHub failed`, error);
       this.setState({ verifying: false, error: true });
       return;
     }
 
-    this.props.appState.gitHubToken = this.state.tokenInput;
     this.props.appState.isTokenDialogShowing = false;
-
-    this.setState({ verifying: false, error: false });
   }
 
   /**

src/renderer/components/dialog-warning.tsx

@@ -1,52 +0,0 @@
-
-import { Alert, Intent } from '@blueprintjs/core';
-import { observer } from 'mobx-react';
-import * as React from 'react';
-
-import { AppState } from '../state';
-
-export interface WarningDialogProps {
-  appState: AppState;
-}
-
-export interface WarningDialogState {
-}
-
-/**
- * The token dialog asks the user for a GitHub Personal Access Token.
- * It's also responsible for checking if the token is correct.
- *
- * @export
- * @class WarningDialog
- * @extends {React.Component<WarningDialogProps, WarningDialogState>}
- */
-@observer
-export class WarningDialog extends React.Component<WarningDialogProps, WarningDialogState> {
-  constructor(props: WarningDialogProps) {
-    super(props);
-
-    this.onClose = this.onClose.bind(this);
-  }
-
-  public onClose(result: boolean) {
-    this.props.appState.warningDialogLastResult = result;
-    this.props.appState.toogleWarningDialog();
-  }
-
-  public render() {
-    const { isWarningDialogShowing, warningDialogTexts } = this.props.appState;
-
-    return (
-      <Alert
-        isOpen={isWarningDialogShowing}
-        onClose={this.onClose}
-        icon='warning-sign'
-        confirmButtonText={warningDialogTexts.ok}
-        cancelButtonText={warningDialogTexts.cancel}
-        intent={Intent.DANGER}
-      >
-        <p>{warningDialogTexts.label}</p>
-      </Alert>
-    );
-  }
-}

src/renderer/components/dialogs.tsx

@@ -2,9 +2,11 @@ import { observer } from 'mobx-react';
 import * as React from 'react';
 
 import { AppState } from '../state';
+import { AddThemeDialog } from './dialog-add-theme';
 import { AddVersionDialog } from './dialog-add-version';
+import { BisectDialog } from './dialog-bisect';
+import { GenericDialog } from './dialog-generic';
 import { TokenDialog } from './dialog-token';
-import { WarningDialog } from './dialog-warning';
 import { Settings } from './settings';
 
 export interface DialogsProps {
@@ -21,7 +23,14 @@ export interface DialogsProps {
 export class Dialogs extends React.Component<DialogsProps, {}> {
   public render() {
     const { appState } = this.props;
-    const { isTokenDialogShowing, isSettingsShowing, isAddVersionDialogShowing } = appState;
+    const {
+      isTokenDialogShowing,
+      isSettingsShowing,
+      isAddVersionDialogShowing,
+      isThemeDialogShowing,
+      isBisectDialogShowing,
+      isGenericDialogShowing
+    } = appState;
     const maybeToken = isTokenDialogShowing
       ? <TokenDialog key='dialogs' appState={appState} />
       : null;
@@ -31,13 +40,23 @@ export class Dialogs extends React.Component<DialogsProps, {}> {
     const maybeAddLocalVersion = isAddVersionDialogShowing
       ? <AddVersionDialog key='add-version-dialog' appState={appState} />
       : null;
+    const maybeMonaco = isThemeDialogShowing ? <AddThemeDialog appState={appState} />
+      : null;
+    const maybeBisect = isBisectDialogShowing
+      ? <BisectDialog key='bisect-dialog' appState={appState} />
+      : null;
+    const genericDialog = isGenericDialogShowing
+      ? <GenericDialog appState={appState} />
+      : null;
 
     return (
       <div key='dialogs' className='dialogs'>
         {maybeToken}
         {maybeSettings}
         {maybeAddLocalVersion}
-        <WarningDialog appState={appState} />
+        {maybeMonaco}
+        {maybeBisect}
+        {genericDialog}
       </div>
     );
   }

src/renderer/components/editor.tsx

@@ -4,17 +4,19 @@
 import * as MonacoType from 'monaco-editor';
 import * as React from 'react';
 
-import { ContentNames, getContent } from '../content';
+import { EditorId } from '../../interfaces';
+import { getContent } from '../content';
 import { AppState } from '../state';
 
 export interface EditorProps {
   appState: AppState;
   monaco: typeof MonacoType;
-  monoacoOptions: MonacoType.editor.IEditorOptions;
-  id: string;
+  monacoOptions: MonacoType.editor.IEditorOptions;
+  id: EditorId;
   options?: Partial<MonacoType.editor.IEditorConstructionOptions>;
   editorDidMount?: (editor: MonacoType.editor.IStandaloneCodeEditor) => void;
   onChange?: (value: string, event: MonacoType.editor.IModelContentChangedEvent) => void;
+  setFocused: (id: EditorId) => void;
 }
 
 export class Editor extends React.Component<EditorProps> {
@@ -26,7 +28,6 @@ export class Editor extends React.Component<EditorProps> {
 
   constructor(props: EditorProps) {
     super(props);
-
     this.language = props.id === 'html' ? 'html' : 'javascript';
   }
 
@@ -48,11 +49,16 @@ export class Editor extends React.Component<EditorProps> {
    *
    * @param {MonacoType.editor.IStandaloneCodeEditor} editor
    */
-  public editorDidMount(editor: MonacoType.editor.IStandaloneCodeEditor) {
+  public async editorDidMount(editor: MonacoType.editor.IStandaloneCodeEditor) {
     const { editorDidMount } = this.props;
 
+    // Set the content on the editor
+    await this.setContent();
+
+    // Set the editor as an available object
     window.ElectronFiddle.editors[this.props.id] = editor;
 
+    // And notify others
     if (editorDidMount) {
       editorDidMount(editor);
     }
@@ -62,8 +68,7 @@ export class Editor extends React.Component<EditorProps> {
    * Initialize Monaco.
    */
   public async initMonaco() {
-    const { monaco, id, appState, monoacoOptions } = this.props;
-    const { version } = appState;
+    const { monaco, monacoOptions: monacoOptions } = this.props;
     const ref = this.containerRef.current;
 
     if (ref) {
@@ -71,10 +76,17 @@ export class Editor extends React.Component<EditorProps> {
         language: this.language,
         theme: 'main',
         contextmenu: false,
-        value: await getContent(id as ContentNames, version),
-        ...monoacoOptions
+        model: null,
+        ...monacoOptions
       });
-      this.editorDidMount(this.editor);
+
+      // mark this editor as focused whenever it is
+      this.editor.onDidFocusEditorText(() => {
+        const { id, setFocused } = this.props;
+        setFocused(id);
+      });
+
+      await this.editorDidMount(this.editor);
     }
   }
 
@@ -83,6 +95,7 @@ export class Editor extends React.Component<EditorProps> {
    */
   public destroyMonaco() {
     if (typeof this.editor !== 'undefined') {
+      console.log('Editor: Disposing');
       this.editor.dispose();
     }
   }
@@ -90,4 +103,54 @@ export class Editor extends React.Component<EditorProps> {
   public render() {
     return <div className='editorContainer' ref={this.containerRef} />;
   }
+
+  /**
+   * Create a model and attach it to the editor
+   *
+   * @private
+   * @param {string} value
+   */
+  private async createModel(value: string) {
+    const { monaco } = this.props;
+
+    const model = monaco.editor.createModel(value, this.language);
+    model.updateOptions({
+      tabSize: 2
+    });
+
+    this.editor.setModel(model);
+  }
+
+  /**
+   * Sets the content on the editor, including the model and the view state.
+   *
+   * @private
+   * @memberof Editor
+   */
+  private async setContent() {
+    const { appState, id } = this.props;
+    const { version } = appState;
+
+    const backup = appState.getAndRemoveEditorValueBackup(id);
+
+    console.log(id);
+
+    if (backup) {
+      console.log(`Editor: Backup found, restoring state`);
+
+      if (backup.viewState) {
+        this.editor.restoreViewState(backup.viewState);
+      }
+
+      // If there's a model, use the model. No model? Use the value
+      if (backup.model) {
+        this.editor.setModel(backup.model);
+      } else if (typeof backup.value !== 'undefined') {
+        this.createModel(backup.value);
+      }
+    } else {
+      const value = await getContent(id, version);
+      await this.createModel(value);
+    }
+  }
 }

src/renderer/components/editors-non-ideal-state.tsx

@@ -0,0 +1,24 @@
+import * as React from 'react';
+
+import { Button, NonIdealState } from '@blueprintjs/core';
+
+import { EditorId } from '../../interfaces';
+import { AppState } from '../state';
+
+export function renderNonIdealState(appState: AppState) {
+  const allEditors = [ EditorId.html, EditorId.main, EditorId.renderer ];
+  const resolveButton = (
+    <Button
+      text='Open all editors'
+      onClick={() => appState.setVisibleMosaics(allEditors)}
+    />
+  );
+
+  return (
+    <NonIdealState
+      action={resolveButton}
+      icon='applications'
+      description='You have closed all editors. You can open them again with the button below or the "Editors" button above!'
+    />
+  );
+}

src/renderer/components/editors-toolbar-button.tsx

@@ -0,0 +1,88 @@
+import * as React from 'react';
+
+import { Button } from '@blueprintjs/core';
+import { MosaicContext, MosaicRootActions, MosaicWindowContext } from 'react-mosaic-component';
+
+import { DocsDemoPage, MosaicId } from '../../interfaces';
+import { AppState } from '../state';
+
+export interface ToolbarButtonProps {
+  appState: AppState;
+  id: MosaicId;
+}
+
+export abstract class ToolbarButton extends React.PureComponent<ToolbarButtonProps> {
+  public static contextType = MosaicWindowContext;
+  public context: MosaicWindowContext;
+
+  constructor(props: ToolbarButtonProps) {
+    super(props);
+  }
+
+  public render() {
+    return (
+      <MosaicContext.Consumer>
+        {({ mosaicActions }) => this.createButton(mosaicActions)}
+      </MosaicContext.Consumer>
+    );
+  }
+
+  /**
+   * Create a button that performs the actual action
+   */
+  public abstract createButton(_mosaicActions: MosaicRootActions<any>): React.ReactNode;
+}
+
+export class MaximizeButton extends ToolbarButton {
+  /**
+   * Create a button that can expand this panel
+   */
+  public createButton(mosaicActions: MosaicRootActions<any>) {
+    const onClick = () => {
+      mosaicActions.expand(this.context.mosaicWindowActions.getPath());
+    };
+
+    return (
+      <Button
+        icon='maximize'
+        className='bp3-small'
+        onClick={onClick}
+      />
+    );
+  }
+}
+
+export class RemoveButton extends ToolbarButton {
+  /**
+   * Create a button that can remove this panel
+   */
+  public createButton(_mosaicActions: MosaicRootActions<any>) {
+    const onClick = () => this.props.appState.hideAndBackupMosaic(this.props.id);
+
+    return (
+      <Button
+        icon='cross'
+        className='bp3-small'
+        onClick={onClick}
+      />
+    );
+  }
+}
+
+export class DocsDemoGoHomeButton extends ToolbarButton {
+  /**
+   * Create a button that can remove this panel
+   */
+  public createButton(_mosaicActions: MosaicRootActions<any>) {
+    const onClick = () => this.props.appState.currentDocsDemoPage = DocsDemoPage.DEFAULT;
+
+    return (
+      <Button
+        icon='home'
+        className='bp3-small'
+        onClick={onClick}
+        text='Overview'
+      />
+    );
+  }
+}

src/renderer/components/editors.tsx

@@ -1,28 +1,24 @@
+import { reaction } from 'mobx';
+import { observer } from 'mobx-react';
 import * as MonacoType from 'monaco-editor';
 import * as React from 'react';
-import { Mosaic, MosaicWindow } from 'react-mosaic-component';
+import { Mosaic, MosaicBranch, MosaicNode, MosaicWindow, MosaicWindowProps } from 'react-mosaic-component';
 
-import { EditorId } from '../../interfaces';
+import { EditorId, MosaicId, PanelId } from '../../interfaces';
 import { IpcEvents } from '../../ipc-events';
 import { updateEditorLayout } from '../../utils/editor-layout';
 import { getFocusedEditor } from '../../utils/focused-editor';
 import { getAtPath, setAtPath } from '../../utils/js-path';
 import { toggleMonaco } from '../../utils/toggle-monaco';
-import { ContentNames, getContent } from '../content';
+import { isEditorId } from '../../utils/type-checks';
+import { getContent } from '../content';
 import { ipcRendererManager } from '../ipc';
 import { AppState } from '../state';
 import { activateTheme } from '../themes';
 import { Editor } from './editor';
-
-const options: any = {
-  direction: 'row',
-  first: 'main',
-  second: {
-    direction: 'column',
-    first: 'renderer',
-    second: 'html',
-  },
-};
+import { renderNonIdealState } from './editors-non-ideal-state';
+import { DocsDemoGoHomeButton, MaximizeButton, RemoveButton } from './editors-toolbar-button';
+import { ShowMe } from './show-me';
 
 const defaultMonacoOptions: MonacoType.editor.IEditorOptions = {
   minimap: {
@@ -31,13 +27,12 @@ const defaultMonacoOptions: MonacoType.editor.IEditorOptions = {
   wordWrap: 'on'
 };
 
-const ViewIdMosaic = Mosaic.ofType<EditorId>() as any;
-const ViewIdMosaicWindow = MosaicWindow.ofType<EditorId>() as any;
-
-const TITLE_MAP: Record<EditorId, string> = {
-  main: 'Main Process',
-  renderer: 'Renderer Process',
-  html: 'HTML'
+export const TITLE_MAP: Record<MosaicId, string> = {
+  main: 'Main Process (main.js)',
+  renderer: 'Renderer Process (renderer.js)',
+  preload: 'Preload (preload.js)',
+  html: 'HTML (index.html)',
+  docsDemo: 'Docs & Demos',
 };
 
 export interface EditorsProps {
@@ -48,15 +43,37 @@ export interface EditorsState {
   monaco?: typeof MonacoType;
   isMounted?: boolean;
   monacoOptions: MonacoType.editor.IEditorOptions;
+  focused?: EditorId;
 }
 
+@observer
 export class Editors extends React.Component<EditorsProps, EditorsState> {
+  // A reaction: Each time mosaicArrangement is changed, we'll update
+  // the editor layout. That method is itself debounced.
+  public disposeLayoutAutorun = reaction(
+    () => this.props.appState.mosaicArrangement,
+    () => updateEditorLayout()
+  );
+
   constructor(props: EditorsProps) {
     super(props);
+
+    this.onChange = this.onChange.bind(this);
+    this.renderEditor = this.renderEditor.bind(this);
+    this.renderTile = this.renderTile.bind(this);
+    this.renderGenericPanel = this.renderGenericPanel.bind(this);
+    this.setFocused = this.setFocused.bind(this);
+
     this.state = { monacoOptions: defaultMonacoOptions };
+
     this.loadMonaco();
   }
 
+  /**
+   * Executed right after the component mounts. We'll setup the IPC listeners here.
+   *
+   * @memberof Editors
+   */
   public componentDidMount() {
     ipcRendererManager.on(IpcEvents.MONACO_EXECUTE_COMMAND, (_event, cmd: string) => {
       this.executeCommand(cmd);
@@ -65,15 +82,11 @@ export class Editors extends React.Component<EditorsProps, EditorsState> {
     ipcRendererManager.on(IpcEvents.FS_NEW_FIDDLE, async (_event) => {
       const { version } = this.props.appState;
 
-      this.props.appState.setWarningDialogTexts({
-        label: 'Your current fiddle is unsaved. Do you want to discard it?'
-      });
-
-      window.ElectronFiddle.app.setValues({
-        html: await getContent(ContentNames.HTML, version),
-        renderer: await getContent(ContentNames.RENDERER, version),
-        main: await getContent(ContentNames.MAIN, version),
-      });
+      await window.ElectronFiddle.app.replaceFiddle({
+        html: await getContent(EditorId.html, version),
+        renderer: await getContent(EditorId.renderer, version),
+        main: await getContent(EditorId.main, version),
+      }, {});
     });
 
     ipcRendererManager.on(IpcEvents.MONACO_TOGGLE_OPTION, (_event, cmd: string) => {
@@ -83,6 +96,10 @@ export class Editors extends React.Component<EditorsProps, EditorsState> {
     this.setState({ isMounted: true });
   }
 
+  public componentWillUnmount() {
+    this.disposeLayoutAutorun();
+  }
+
   /**
    * Attempt to execute a given commandId on the currently focused editor
    *
@@ -135,27 +152,124 @@ export class Editors extends React.Component<EditorsProps, EditorsState> {
     }
   }
 
+  /**
+   * Renders the little tool bar on top of each panel
+   *
+   * @param {MosaicWindowProps<MosaicId>} { title }
+   * @param {MosaicId} id
+   * @returns {JSX.Element}
+   */
+  public renderToolbar(
+    { title }: MosaicWindowProps<MosaicId>, id: MosaicId
+  ): JSX.Element {
+    const docsDemoGoHomeMaybe = id === PanelId.docsDemo
+      ? <DocsDemoGoHomeButton id={id} appState={this.props.appState} />
+      : null;
+
+    return (
+      <div>
+        {/* Left */}
+        <div>
+          <h5>
+            {title}
+          </h5>
+        </div>
+        {/* Middle */}
+        <div />
+        {/* Right */}
+        <div className='mosaic-controls'>
+          {docsDemoGoHomeMaybe}
+          <MaximizeButton id={id} appState={this.props.appState} />
+          <RemoveButton id={id} appState={this.props.appState} />
+        </div>
+      </div>
+    );
+  }
+
+  /**
+   * Renders a Mosaic tile
+   *
+   * @param {string} id
+   * @param {string} path
+   * @returns {JSX.Element | null}
+   */
+  public renderTile(id: MosaicId, path: Array<MosaicBranch>): JSX.Element {
+    const { appState } = this.props;
+    const content = isEditorId(id)
+      ? this.renderEditor(id)
+      : this.renderGenericPanel(id, appState);
+
+    return (
+      <MosaicWindow<EditorId>
+        className={id}
+        path={path}
+        title={TITLE_MAP[id]}
+        renderToolbar={(props: MosaicWindowProps<MosaicId>) => this.renderToolbar(props, id)}
+      >
+        {content}
+      </MosaicWindow>
+    );
+  }
+
+  /**
+   * Renders a generic panel – so not an editor, but something else
+   *
+   * @param {PanelId} _id
+   * @param {AppState} _appState
+   * @returns {JSX.Element}
+   */
+  public renderGenericPanel(_id: PanelId, appState: AppState): JSX.Element {
+    return <ShowMe appState={appState} />;
+  }
+
+  /**
+   * Render an editor
+   *
+   * @param {EditorId} id
+   * @returns {(JSX.Element | null)}
+   * @memberof Editors
+   */
+  public renderEditor(id: EditorId): JSX.Element | null {
+    const { appState } = this.props;
+    const { monaco } = this.state;
+
+    return (
+      <Editor
+        id={id}
+        monaco={monaco!}
+        appState={appState}
+        monacoOptions={defaultMonacoOptions}
+        setFocused={this.setFocused}
+      />
+    );
+  }
+
   public render() {
     const { appState } = this.props;
     const { monaco } = this.state;
 
     if (!monaco) return null;
 
-
     return (
-      <ViewIdMosaic
-        onChange={updateEditorLayout}
-        // tslint:disable-next-line:jsx-no-multiline-js
-        renderTile={(id: any, path: any) => (
-          <ViewIdMosaicWindow className={id} path={path} title={TITLE_MAP[id]} toolbarControls={<div />}>
-            <Editor id={id} monaco={monaco} appState={appState} monoacoOptions={defaultMonacoOptions} />
-          </ViewIdMosaicWindow>
-        )}
-        initialValue={options}
+      <Mosaic<EditorId | PanelId>
+        className={`focused__${this.state.focused}`}
+        onChange={this.onChange}
+        value={appState.mosaicArrangement}
+        zeroStateView={renderNonIdealState(appState)}
+        renderTile={this.renderTile}
       />
     );
   }
 
+  /**
+   * Handles a change in the visible nodes
+   *
+   * @param {(MosaicNode<EditorId> | null)} currentNode
+   */
+  public onChange(currentNode: MosaicNode<EditorId> | null) {
+    this.props.appState.mosaicArrangement = currentNode;
+  }
+
   /**
    * Loads monaco. If it's already loaded, it'll just set it on the current state.
    * We're doing things a bit roundabout to ensure that we're not overloading the
@@ -171,11 +285,24 @@ export class Editors extends React.Component<EditorsProps, EditorsState> {
     }
 
     if (!this.state || !this.state.isMounted) {
-      this.state = { monaco, monacoOptions: defaultMonacoOptions };
+      this.state = {
+        monaco,
+        monacoOptions: defaultMonacoOptions
+      };
     } else {
       this.setState({ monaco });
     }
 
     activateTheme(monaco, undefined, this.props.appState.theme);
   }
+
+  /**
+   * Sets the currently-focused editor. This will impact the editor's
+   * z-index, ensuring that its intellisense menus don't get clipped
+   * by the other editor windows.
+   * @param id Editor ID
+   */
+  public setFocused(id: EditorId): void {
+    this.setState({ focused: id });
+  }
 }

src/renderer/components/header.tsx

@@ -3,7 +3,6 @@ import * as React from 'react';
 import { AppState } from '../state';
 import { ChromeMac } from './chrome-mac';
 import { Commands } from './commands';
-import { Output } from './output';
 import { WelcomeTour } from './tour-welcome';
 
 export interface HeaderProps {
@@ -23,7 +22,6 @@ export class Header extends React.Component<HeaderProps, {}> {
         <ChromeMac appState={this.props.appState} />
         <header id='header'>
           <Commands key='commands' appState={this.props.appState} />
-          <Output key='output' appState={this.props.appState} />
         </header>
         <WelcomeTour appState={this.props.appState} />
       </>

src/renderer/components/output-editors-wrapper.tsx

@@ -0,0 +1,59 @@
+import * as React from 'react';
+import { Mosaic, MosaicNode } from 'react-mosaic-component';
+
+import { AppState } from '../state';
+import { Editors } from './editors';
+import { Output } from './output';
+
+export interface WrapperProps {
+  appState: AppState;
+}
+
+export interface WrapperState {
+  mosaicArrangement: MosaicNode<WrapperMosaicId>;
+}
+
+export type WrapperMosaicId = 'output' | 'editors';
+
+export class OutputEditorsWrapper extends React.Component<WrapperProps, WrapperState> {
+
+  private MOSAIC_ELEMENTS = {
+    output: <Output appState={this.props.appState} />,
+    editors: <Editors appState={this.props.appState} />
+  };
+
+  constructor(props: any) {
+    super(props);
+    this.state = {
+      mosaicArrangement: {
+        direction: 'column',
+        first: 'output',
+        second: 'editors',
+        splitPercentage: 25,
+      }
+    };
+  }
+
+  public render() {
+    return (
+      <>
+        <Mosaic<WrapperMosaicId>
+          renderTile={(id: string) => this.MOSAIC_ELEMENTS[id]}
+          resize={{minimumPaneSizePercentage: 0}}
+          value={this.state.mosaicArrangement}
+          onChange={this.onChange}
+        />
+      </>
+    );
+  }
+
+  private onChange = (currentNode: any) => {
+    const isConsoleShowing = currentNode.splitPercentage !== 0;
+
+    if (isConsoleShowing !== this.props.appState.isConsoleShowing) {
+      this.props.appState.isConsoleShowing = isConsoleShowing;
+    }
+
+    this.setState({mosaicArrangement: currentNode});
+  }
+}

src/renderer/components/output.tsx

@@ -1,8 +1,12 @@
+import { autorun } from 'mobx';
 import { observer } from 'mobx-react';
 import * as React from 'react';
+import { MosaicContext } from 'react-mosaic-component';
 
 import { OutputEntry } from '../../interfaces';
 import { AppState } from '../state';
+import { WrapperMosaicId } from './output-editors-wrapper';
+
 
 export interface CommandsProps {
   appState: AppState;
@@ -19,6 +23,8 @@ export interface CommandsProps {
  */
 @observer
 export class Output extends React.Component<CommandsProps, {}> {
+  public static contextType = MosaicContext;
+  public context: MosaicContext<WrapperMosaicId>;
   private outputRef = React.createRef<HTMLDivElement>();
 
   constructor(props: CommandsProps) {
@@ -28,6 +34,23 @@ export class Output extends React.Component<CommandsProps, {}> {
     this.renderEntry = this.renderEntry.bind(this);
   }
 
+
+  public componentDidMount() {
+    autorun(() => {
+      const { isConsoleShowing } = this.props.appState;
+
+      // this context should always exist, but mocking context in enzyme
+      // is not fully supported, so this condition makes the tests pass
+      if (this.context.mosaicActions && this.context.mosaicActions.expand) {
+        if (!isConsoleShowing) {
+          this.context.mosaicActions.expand(['first'], 0);
+        } else {
+          this.context.mosaicActions.expand(['first'], 25);
+        }
+      }
+    });
+  }
+
   public componentDidUpdate() {
     if (this.outputRef.current) {
       this.outputRef.current.scrollTop = this.outputRef.current.scrollHeight;
@@ -71,9 +94,12 @@ export class Output extends React.Component<CommandsProps, {}> {
     ));
   }
 
-  public render() {
-    const { isConsoleShowing, output } = this.props.appState;
-    const className = isConsoleShowing ? 'output showing' : 'output';
+  public render(): JSX.Element | null {
+    const { output, isConsoleShowing } = this.props.appState;
+
+    if (!isConsoleShowing) {
+      return null;
+    }
 
     // The last 1000 lines
     const lines = output
@@ -81,7 +107,7 @@ export class Output extends React.Component<CommandsProps, {}> {
       .map(this.renderEntry);
 
     return (
-      <div className={className} ref={this.outputRef}>
+      <div className='output' ref={this.outputRef}>
         {lines}
       </div>
     );

src/renderer/components/settings-electron.tsx

@@ -41,6 +41,7 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
     this.handleDownloadAll = this.handleDownloadAll.bind(this);
     this.handleDeleteAll = this.handleDeleteAll.bind(this);
     this.handleChannelChange = this.handleChannelChange.bind(this);
+    this.handleStateChange = this.handleStateChange.bind(this);
     this.handleDownloadClick = this.handleDownloadClick.bind(this);
     this.handleAddVersion = this.handleAddVersion.bind(this);
 
@@ -54,6 +55,24 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
     this.props.appState.updateElectronVersions();
   }
 
+  /**
+   * Handles a change in which channels should be displayed.
+   *
+   * @param {React.ChangeEvent<HTMLInputElement>} event
+   */
+  public handleStateChange(
+    event: React.FormEvent<HTMLInputElement>
+  ) {
+    const { id, checked } = event.currentTarget;
+    const { appState } = this.props;
+
+    if (!checked) {
+      appState.statesToShow = appState.statesToShow.filter((s) => s !== id);
+    } else {
+      appState.statesToShow.push(id as ElectronVersionState);
+    }
+  }
+
   /**
    * Handles a change in which channels should be displayed.
    *
@@ -66,9 +85,9 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
     const { appState } = this.props;
 
     if (!checked) {
-      appState.versionsToShow = appState.versionsToShow.filter((c) => c !== id);
+      appState.channelsToShow = appState.channelsToShow.filter((c) => c !== id);
     } else {
-      appState.versionsToShow.push(id as ElectronReleaseChannel);
+      appState.channelsToShow.push(id as ElectronReleaseChannel);
     }
   }
 
@@ -120,7 +139,10 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
     return (
       <div className='settings-electron'>
         <h2>Electron Settings</h2>
-        {this.renderVersionOptions()}
+        <Callout>
+          {this.renderVersionChannelOptions()}
+          {this.renderVersionStateOptions()}
+        </Callout>
         <br />
         <Callout>
           {this.renderAdvancedButtons()}
@@ -173,51 +195,91 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
 
   /**
    * Renders the various options for which versions should be displayed
+   * in the small dropdown.
    *
    * @private
    * @returns {JSX.Element}
    */
-  private renderVersionOptions(): JSX.Element {
+  private renderVersionStateOptions(): JSX.Element {
     const { appState } = this.props;
-    const getIsChecked = (channel: ElectronReleaseChannel) => {
-      return appState.versionsToShow.includes(channel);
+    const getIsChecked = (state: ElectronVersionState) => {
+      return appState.statesToShow.includes(state);
     };
 
     return (
-      <Callout>
-        <FormGroup
-          label='Include Electron versions from these release channels:'
-        >
-          <Checkbox
-            checked={getIsChecked(ElectronReleaseChannel.stable)}
-            label='Stable'
-            id='Stable'
-            onChange={this.handleChannelChange}
-            inline={true}
-          />
-          <Checkbox
-            checked={getIsChecked(ElectronReleaseChannel.beta)}
-            label='Beta'
-            id='Beta'
-            onChange={this.handleChannelChange}
-            inline={true}
-          />
-          <Checkbox
-            checked={getIsChecked(ElectronReleaseChannel.nightly)}
-            label='Nightly'
-            id='Nightly'
-            onChange={this.handleChannelChange}
-            inline={true}
-          />
-          <Checkbox
-            checked={getIsChecked(ElectronReleaseChannel.unsupported)}
-            label='Unsupported'
-            id='Unsupported'
-            onChange={this.handleChannelChange}
-            inline={true}
-          />
-        </FormGroup>
-      </Callout>
+      <FormGroup
+        label='Include Electron versions that are:'
+      >
+        <Checkbox
+          checked={getIsChecked(ElectronVersionState.downloading)}
+          label='Downloading'
+          id='downloading'
+          onChange={this.handleStateChange}
+          inline={true}
+        />
+        <Checkbox
+          checked={getIsChecked(ElectronVersionState.ready)}
+          label='Downloaded'
+          id='ready'
+          onChange={this.handleStateChange}
+          inline={true}
+        />
+        <Checkbox
+          checked={getIsChecked(ElectronVersionState.unknown)}
+          label='Not Downloaded'
+          id='unknown'
+          onChange={this.handleStateChange}
+          inline={true}
+        />
+      </FormGroup>
+    );
+  }
+
+  /**
+   * Renders the various options for which versions should be displayed
+   *
+   * @private
+   * @returns {JSX.Element}
+   */
+  private renderVersionChannelOptions(): JSX.Element {
+    const { appState } = this.props;
+    const getIsChecked = (channel: ElectronReleaseChannel) => {
+      return appState.channelsToShow.includes(channel);
+    };
+
+    return (
+      <FormGroup
+        label='Include Electron versions from these release channels:'
+      >
+        <Checkbox
+          checked={getIsChecked(ElectronReleaseChannel.stable)}
+          label='Stable'
+          id='Stable'
+          onChange={this.handleChannelChange}
+          inline={true}
+        />
+        <Checkbox
+          checked={getIsChecked(ElectronReleaseChannel.beta)}
+          label='Beta'
+          id='Beta'
+          onChange={this.handleChannelChange}
+          inline={true}
+        />
+        <Checkbox
+          checked={getIsChecked(ElectronReleaseChannel.nightly)}
+          label='Nightly'
+          id='Nightly'
+          onChange={this.handleChannelChange}
+          inline={true}
+        />
+        <Checkbox
+          checked={getIsChecked(ElectronReleaseChannel.unsupported)}
+          label='Unsupported'
+          id='Unsupported'
+          onChange={this.handleChannelChange}
+          inline={true}
+        />
+      </FormGroup>
     );
   }
 
@@ -254,11 +316,16 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
    * @returns {Array<JSX.Element>}
    */
   private renderTableRows(): Array<JSX.Element | null> {
-    const { versions, versionsToShow } = this.props.appState;
+    const { versions, channelsToShow, statesToShow } = this.props.appState;
 
     return sortedElectronMap<JSX.Element | null>(versions, (key, item) => {
       // Check if we want to show the version
-      if (!versionsToShow.includes(getReleaseChannel(item))) {
+      if (!channelsToShow.includes(getReleaseChannel(item))) {
+        return null;
+      }
+
+      // Check if we want to show the state
+      if (!statesToShow.includes(item.state)) {
         return null;
       }
 
@@ -273,7 +340,7 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
   }
 
   /**
-   * Returns a human-readable state indicator for an Electorn version
+   * Returns a human-readable state indicator for an Electron version
    *
    * @param {ElectronVersion} item
    * @returns {JSX.Element}
@@ -334,6 +401,6 @@ export class ElectronSettings extends React.Component<ElectronSettingsProps, Ele
       buttonProps.onClick = () => appState.downloadVersion(key);
     }
 
-    return <Button {...buttonProps} />;
+    return <Button {...buttonProps} type={undefined} />;
   }
 }

src/renderer/components/settings-execution.tsx

@@ -1,4 +1,4 @@
-import { Callout, Checkbox, FormGroup } from '@blueprintjs/core';
+import { Callout, Checkbox, FormGroup, InputGroup } from '@blueprintjs/core';
 import { observer } from 'mobx-react';
 import * as React from 'react';
 
@@ -20,6 +20,8 @@ export class ExecutionSettings extends React.Component<ExecutionSettingsProps, {
     super(props);
 
     this.handleDeleteDataChange = this.handleDeleteDataChange.bind(this);
+    this.handleElectronLoggingChange = this.handleElectronLoggingChange.bind(this);
+    this.handleExecutionFlagChange = this.handleExecutionFlagChange.bind(this);
   }
 
   /**
@@ -35,31 +37,94 @@ export class ExecutionSettings extends React.Component<ExecutionSettingsProps, {
     this.props.appState.isKeepingUserDataDirs = checked;
   }
 
+  /**
+   * Handles a change on whether or not electron should log more things
+   *
+   * @param {React.ChangeEvent<HTMLInputElement>} event
+   */
+  public handleElectronLoggingChange(
+    event: React.FormEvent<HTMLInputElement>
+  ) {
+    const { checked } = event.currentTarget;
+    this.props.appState.isEnablingElectronLogging = checked;
+  }
+
+  /**
+   * Handles a change in the execution flags run with the Electron executable
+   *
+   * @param {React.ChangeEvent<HTMLInputElement>} event
+   */
+  public handleExecutionFlagChange(
+    event: React.FormEvent<HTMLInputElement>
+  ) {
+    const { value } = event.currentTarget;
+    const flags = value.split('|');
+    this.props.appState.executionFlags = flags;
+  }
+
   public render() {
-    const { isKeepingUserDataDirs } = this.props.appState;
+    const {
+      isKeepingUserDataDirs,
+      isEnablingElectronLogging,
+      executionFlags = []
+    } = this.props.appState;
+
     const deleteUserDirLabel = `
       Whenever Electron runs, it creates a user data directory for cookies, the cache,
       and various other things that it needs to keep around. Since fiddles are usually
       just run once, we delete this directory after your fiddle exits. Enable this
       setting to keep the user data directories around.
     `.trim();
+    const electronLoggingLabel = `
+      There are some flags that Electron uses to log extra information both internally
+      and through Chromium.  Enable this option to make Fiddle produce those logs.`.trim();
 
     return (
       <div>
-        <h2>Exection</h2>
+        <h2>Execution</h2>
         <Callout>
           These advanced settings control how Electron Fiddle executes your fiddles.
         </Callout>
         <br />
         <Callout>
-        <FormGroup label={deleteUserDirLabel}>
-          <Checkbox
-            checked={isKeepingUserDataDirs}
-            label='Do not delete user data directories.'
-            onChange={this.handleDeleteDataChange}
-          />
-        </FormGroup>
-      </Callout>
+          <FormGroup label={deleteUserDirLabel}>
+            <Checkbox
+              checked={isKeepingUserDataDirs}
+              label='Do not delete user data directories.'
+              onChange={this.handleDeleteDataChange}
+            />
+          </FormGroup>
+        </Callout>
+        <br />
+        <Callout>
+          <FormGroup label={electronLoggingLabel}>
+            <Checkbox
+              checked={isEnablingElectronLogging}
+              label='Enable advanced Electron logging.'
+              onChange={this.handleElectronLoggingChange}
+            />
+          </FormGroup>
+        </Callout>
+        <br />
+        <Callout>
+          <FormGroup>
+          <p>
+            Electron allows starting the executable with <a
+              href='https://electronjs.org/docs/api/chrome-command-line-switches'
+            >
+              user-provided flags
+            </a>
+            , such as '--js-flags=--expose-gc'. Those can be added here as bar-separated (|)
+            flags to run when you start your Fiddles.
+          </p>
+            <br />
+            <InputGroup
+              placeholder='--js-flags=--expose-gc|--lang=es'
+              value={executionFlags.join('|')}
+              onChange={this.handleExecutionFlagChange}
+            />
+          </FormGroup>
+        </Callout>
       </div>
     );
   }

src/renderer/components/settings-general-appearance.tsx

@@ -76,6 +76,7 @@ export class AppearanceSettings extends React.Component<
 
     this.handleChange = this.handleChange.bind(this);
     this.openThemeFolder = this.openThemeFolder.bind(this);
+    this.handleAddTheme = this.handleAddTheme.bind(this);
 
     this.state = {
       themes: []
@@ -111,8 +112,9 @@ export class AppearanceSettings extends React.Component<
    * @memberof AppearanceSettings
    */
   public async createNewThemeFromCurrent(): Promise<boolean> {
+    const { appState } = this.props;
     const fs = await fancyImport<typeof fsType>('fs-extra');
-    const theme = await getTheme(this.props.appState.theme);
+    const theme = await getTheme(appState.theme);
 
     try {
       const namor = await fancyImport<any>('namor');
@@ -128,6 +130,8 @@ export class AppearanceSettings extends React.Component<
 
       shell.showItemInFolder(themePath);
 
+      this.setState({themes: await getAvailableThemes()});
+
       return true;
     } catch (error) {
       console.warn(`Themes: Failed to create new theme from current`, error);
@@ -190,13 +194,29 @@ export class AppearanceSettings extends React.Component<
             </a>. The easiest way to get started is to clone one of the two existing
             themes and to add your own colors.
           </p>
+          <p>
+            Additionally, if you wish to import a Monaco Editor theme, pick your JSON file and Fiddle will attempt to import it.
+          </p>
           <Button
             onClick={this.createNewThemeFromCurrent}
             text='Create theme from current selection'
             icon='duplicate'
           />
+          <Button
+            icon='document-open'
+            onClick={this.handleAddTheme}
+            text='Add a Monaco Editor theme'
+          />
         </Callout>
       </div>
     );
   }
+
+  /**
+   * Opens the "add monaco theme" dialog
+   */
+  public handleAddTheme(): void {
+    this.props.appState.toggleAddMonacoThemeDialog();
+  }
+
 }

src/renderer/components/settings-general-console.tsx

@@ -0,0 +1,60 @@
+import { Callout, Checkbox, FormGroup } from '@blueprintjs/core';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { AppState } from '../state';
+
+export interface ConsoleSettingsProps {
+  appState: AppState;
+}
+
+/**
+ * Settings content to manage console-related preferences.
+ *
+ * @class ConsoleSettings
+ * @extends {React.Component<ConsoleSettingsProps, {}>}
+ */
+@observer
+export class ConsoleSettings extends React.Component<ConsoleSettingsProps, {}> {
+  constructor(props: ConsoleSettingsProps) {
+    super(props);
+
+    this.handleClearOnRunChange = this.handleClearOnRunChange.bind(this);
+  }
+
+  /**
+   * Handles a change on whether or not the console should be cleared
+   * before fiddle is executed.
+   *
+   * @param {React.ChangeEvent<HTMLInputElement>} event
+   */
+  public handleClearOnRunChange(
+    event: React.FormEvent<HTMLInputElement>
+  ) {
+    const { checked } = event.currentTarget;
+    this.props.appState.isClearingConsoleOnRun = checked;
+  }
+
+  public render() {
+    const { isClearingConsoleOnRun } = this.props.appState;
+
+    const clearOnRunLabel = `
+      Enable this option to automatically clear the console whenever you run your
+      fiddle.`.trim();
+
+    return (
+      <div>
+        <h4>Console</h4>
+        <Callout>
+          <FormGroup label={clearOnRunLabel}>
+            <Checkbox
+              checked={isClearingConsoleOnRun}
+              label='Clear on run.'
+              onChange={this.handleClearOnRunChange}
+            />
+          </FormGroup>
+        </Callout>
+      </div>
+    );
+  }
+}

src/renderer/components/settings-general-github.tsx

@@ -31,7 +31,7 @@ export class GitHubSettings extends React.Component<GitHubSettingsProps, {}> {
     return (
       <Callout>
         <p>
-          Your fiddles can be published as public GitHub Gists -
+          Your fiddles can be published as GitHub Gists -
           that way you can share your fiddles with the world!
         </p>
         <Button onClick={this.signIn} icon='log-in' text='Sign in'/>

src/renderer/components/settings-general.tsx

@@ -4,6 +4,7 @@ import * as React from 'react';
 
 import { AppState } from '../state';
 import { AppearanceSettings } from './settings-general-appearance';
+import { ConsoleSettings } from './settings-general-console';
 import { GitHubSettings } from './settings-general-github';
 
 export interface GeneralSettingsProps {
@@ -24,6 +25,8 @@ export class GeneralSettings extends React.Component<GeneralSettingsProps, {}> {
         <h2>General Settings</h2>
         <AppearanceSettings appState={this.props.appState} />
         <Divider />
+        <ConsoleSettings appState={this.props.appState} />
+        <Divider />
         <GitHubSettings appState={this.props.appState} />
       </div>
     );

src/renderer/components/settings.tsx

@@ -44,6 +44,16 @@ export class Settings extends React.Component<SettingsProps, SettingsState> {
     this.state = {
       section: SettingsSections.General
     };
+
+    this.closeSettingsPanel = this.closeSettingsPanel.bind(this);
+  }
+
+  public componentDidMount() {
+    window.addEventListener('keyup', this.closeSettingsPanel, true);
+  }
+
+  public componentWillUnmount() {
+    window.removeEventListener('keyup', this.closeSettingsPanel);
   }
 
   /**
@@ -138,4 +148,14 @@ export class Settings extends React.Component<SettingsProps, SettingsState> {
 
     return 'cog';
   }
+
+  /**
+   * Trigger closing of the settings panel upon Esc
+   */
+  private closeSettingsPanel(event: KeyboardEvent) {
+    const { appState } = this.props;
+    if (event.code === 'Escape') {
+      appState.isSettingsShowing = false;
+    }
+  }
 }

src/renderer/components/show-me.tsx

@@ -0,0 +1,30 @@
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { AppState } from '../state';
+import { DOCS_DEMO_COMPONENTS } from './show-me/index';
+
+export interface ShowMeProps {
+  appState: AppState;
+}
+
+/**3
+ * The root component for "show me" content - the fourth helpful
+ * panel.
+ *
+ * @class ShowMe
+ * @extends {React.Component<ShowMeProps, ShowMeState>}
+ */
+@observer
+export class ShowMe extends React.Component<ShowMeProps, {}> {
+  public render() {
+    const { currentDocsDemoPage: showMeName } = this.props.appState;
+    const Content = DOCS_DEMO_COMPONENTS[showMeName] || DOCS_DEMO_COMPONENTS.DEFAULT;
+
+    return (
+      <div className='show-me-panel'>
+        <Content appState={this.props.appState} />
+      </div>
+    );
+  }
+}

src/renderer/components/show-me/app.tsx

@@ -0,0 +1,142 @@
+import * as React from 'react';
+
+import { Button, Callout, Icon } from '@blueprintjs/core';
+import { remote } from 'electron';
+
+import { renderMoreDocumentation } from './more-information';
+import { getSubsetOnly } from './subset-only';
+
+/**
+ * Show and hide button examples, only rendered on macOS
+ *
+ * @returns {JSX.Element | null}
+ */
+function ShowHide() {
+  if (process.platform !== 'darwin') return null;
+
+  const onClick = () => {
+    remote.app.hide();
+    setTimeout(() => {
+      remote.app.show();
+      remote.app.focus();
+    }, 1500);
+  };
+
+  return (
+    <>
+      <p>This button hides Electron Fiddle right away, showing it again in two seconds.</p>
+      <Button
+        id='show-hide'
+        icon='eye-off'
+        text='Hide Electron Fiddle'
+        onClick={onClick}
+      />
+    </>
+  );
+}
+export function ShowMeApp(_props: any): JSX.Element {
+  const [ secondsLeft, setSeconds ] = React.useState(-1);
+
+  const playFocus = () => {
+    setSeconds(3);
+    setTimeout(() => setSeconds(2), 1000);
+    setTimeout(() => setSeconds(1), 2000);
+    setTimeout(() => {
+      remote.app.focus();
+      setSeconds(-1);
+    }, 3000);
+  };
+
+  const [ paths, setPaths ] = React.useState('');
+  const playPaths = () => {
+    const pathsToQuery = [
+      'home',
+      'appData',
+      'userData',
+      'temp',
+      'downloads',
+      'desktop'
+    ];
+
+    let result = '';
+    pathsToQuery.forEach((item) => {
+      result += `${item}: ${remote.app.getPath(item as any)}\n`;
+    });
+
+    setPaths(result);
+  };
+
+  const [ metrics, setMetrics ] = React.useState('');
+  const playMetrics = () => {
+    setMetrics(JSON.stringify(remote.app.getAppMetrics(), undefined, 2));
+  };
+
+  return (
+    <>
+      <Icon icon='help' iconSize={40} style={{ float: 'left', margin: '0 10px 0 0' }} />
+      <p className='bp3r-running-text'>
+        The <code>app</code> module controls the app's application life-cycle. Most of the
+        events and methods available on this module are responsible for handling how your
+        interacts with the operating system or to set application-wide settings.
+      </p>
+      <h3>API Demos</h3>
+      {getSubsetOnly('app')}
+      <Callout
+        title='Hiding, Showing, Focussing'
+        icon='eye-open'
+      >
+        <p>
+          The app can ask the operating system for window focus. On macOS, it can additionally
+          request that the app be hidden or shown. Give it a try: Click on the button below,
+          focus another app, and wait for two seconds to see Electron Fiddle become the focused
+          app again.
+        </p>
+        <Button
+          id='focus'
+          icon='lightbulb'
+          text={`Focus Electron Fiddle${secondsLeft > 0 ? ` in ${secondsLeft}s` : ''}`}
+          onClick={playFocus}
+        />
+        <ShowHide />
+      </Callout>
+      <Callout
+        title='Paths'
+        icon='folder-open'
+      >
+        <p>
+          Need to query information about various paths in a cross-platform manner? Electron
+          can help. The button queries the operating system for some of them.
+        </p>
+        <Button
+          id='special-paths'
+          icon='play'
+          text={`Get special directory paths`}
+          onClick={playPaths}
+        />
+        <pre id='special-paths-content'>
+          {paths}
+        </pre>
+      </Callout>
+      <Callout
+        title='Process & Device Information'
+        icon='pulse'
+      >
+        <p>
+          Need to query information about the process or system? The <code>app</code> module lets
+          developers query for information about the running app, hardware, and operating system.
+          A good example are process metrics.
+        </p>
+        <Button
+          id='process-metrics'
+          icon='play'
+          text={`Get process metrics`}
+          onClick={playMetrics}
+        />
+        <pre id='process-metrics-content'>
+          {metrics}
+        </pre>
+      </Callout>
+      {renderMoreDocumentation()}
+    </>
+  );
+}

src/renderer/components/show-me/default.tsx

@@ -0,0 +1,43 @@
+import { Button, Icon } from '@blueprintjs/core';
+import * as React from 'react';
+
+import { DocsDemoPage } from '../../../interfaces';
+import { AppState } from '../../state';
+import { DOCS_DEMO_COMPONENTS, DOCS_DEMO_NAMES } from './index';
+import { renderMoreDocumentation } from './more-information';
+
+export function ShowMeDefault(props: { appState: AppState }): JSX.Element {
+  const showMeMenu: Array<JSX.Element> = Object.keys(DOCS_DEMO_COMPONENTS)
+    .filter((key) => key !== DocsDemoPage.DEFAULT)
+    .map((key) => {
+      return (
+        <li key={key}>
+          <Button
+            minimal={true}
+            icon='play'
+            text={DOCS_DEMO_NAMES[key]}
+            onClick={() => (props.appState.currentDocsDemoPage = key as DocsDemoPage)}
+          />
+        </li>
+      );
+  });
+
+  return (
+    <>
+      <Icon icon='help' iconSize={40} style={{ float: 'left', margin: '0 10px 0 0' }} />
+      <p className='bp3r-running-text'>
+        This panel offers useful information about Electron APIs – and
+        easy way to try some of the methods it offers. Fiddle has an example fiddle
+        for every module available in Electron.
+      </p>
+      <p>
+        Clicking on any of the modules below will open up a fiddle showcasing
+        that particular module.
+      </p>
+      <ul className='show-me-list'>
+        {...showMeMenu}
+      </ul>
+      {renderMoreDocumentation()}
+    </>
+  );
+}

src/renderer/components/show-me/index.tsx

@@ -0,0 +1,14 @@
+import { DocsDemoPage } from '../../../interfaces';
+
+import { ShowMeApp } from './app';
+import { ShowMeDefault } from './default';
+
+export const DOCS_DEMO_COMPONENTS: Record<DocsDemoPage, any> = {
+  DEFAULT: ShowMeDefault,
+  DEMO_APP: ShowMeApp
+};
+
+export const DOCS_DEMO_NAMES: Record<DocsDemoPage, string> = {
+  DEFAULT: 'Home',
+  DEMO_APP: 'App Demos'
+};

src/renderer/components/show-me/more-information.tsx

@@ -0,0 +1,32 @@
+import * as React from 'react';
+
+import { shell } from 'electron';
+
+/**
+ * Renders a "more documentation" block, typically used at the end of a "show me" documentation piece.
+ *
+ * @export
+ * @param {string} [url='electronjs.org/docs']
+ * @returns {JSX.Element}
+ */
+export function renderMoreDocumentation(
+  url: string = 'electronjs.org/docs'
+): JSX.Element {
+  const fullUrl = `https://${url}`;
+  const gitHubUrl = `https://github.com/electron/fiddle`;
+
+  return (
+    <>
+      <br />
+      <p className='b3-running-text'>
+        For more documentation, visit <a id='open-url' onClick={() => shell.openExternal(fullUrl)}>{url}</a>, where
+        you can find the full documentation for Electron.
+      </p>
+      <p className='bp3-text-muted'>
+        By the way, Electron Fiddle and the documentation you see here is entirely open source. If you
+        have ideas on how to improve it, we'd love to have your contributions! You can find the
+        repository on <a id='open-github' onClick={() => shell.openExternal(gitHubUrl)}>GitHub</a>.
+      </p>
+    </>
+  );
+}

src/renderer/components/show-me/subset-only.tsx

@@ -0,0 +1,26 @@
+import * as React from 'react';
+
+import { shell } from 'electron';
+
+import { getDocsUrlForModule } from '../../../utils/docs-urls';
+
+/**
+ * Returns a common string we use as a disclaimer to explain that this set of demos
+ * is only meant to be a short demonstration, not displaying all of the modules
+ * abilities.
+ *
+ * @export
+ * @param {string} moduleName
+ * @returns {JSX.Element}
+ */
+export function getSubsetOnly(moduleName: string): JSX.Element {
+  const { full, short } = getDocsUrlForModule(moduleName);
+
+  return (
+    <p className='bp3-running-text'>
+      The following demos display only a subset of what the <code>{moduleName}</code>
+      module is capable of. If you want to see its full abilities, check out the
+      documentation on <a id='open-url' onClick={() => shell.openExternal(full)}>{short}</a>.
+    </p>
+  );
+}

src/renderer/components/tour-welcome.tsx

@@ -29,8 +29,8 @@ export function getWelcomeTour(): Set<TourScriptStep> {
         <>
           <p>
             Electron Fiddle allows you to build little experiments and mini-apps with
-            Electron. Each Fiddle has three files: A main script, a renderer script,
-            and an HTML file.
+            Electron. Each Fiddle has at least three of these files: A main script, a
+            renderer script, a preload script, and an HTML file.
           </p>
           <p>
             If you <code>require()</code> a module, Fiddle will install
@@ -115,7 +115,7 @@ export function getWelcomeTour(): Set<TourScriptStep> {
             a Node.js application is started. The main script runs in the "main
             process". To display a user interface, the main process creates renderer
             processes – usually in the form of windows, which Electron calls
-            <code>BrowserWindow</code>.
+             &nbsp;<code>BrowserWindow</code>.
           </p>
           <p>
             To get started, pretend that the main process is just like a Node.js
@@ -137,10 +137,10 @@ export function getWelcomeTour(): Set<TourScriptStep> {
       content: (
         <p>
           In the default fiddle, this HTML file is loaded in the
-          <code>BrowserWindow</code>. Any HTML, CSS, or JavaScript that works
+          &nbsp;<code>BrowserWindow</code>. Any HTML, CSS, or JavaScript that works
           in a browser will work here, too. In addition, Electron allows you
           to execute Node.js code. Take a close look at the
-            <code>&lt;script /&gt;</code> tag and notice how we can call <code>
+          &nbsp;<code>&lt;script /&gt;</code> tag and notice how we can call <code>
           require()</code> like we would in Node.js.
         </p>
       )
@@ -157,7 +157,7 @@ export function getWelcomeTour(): Set<TourScriptStep> {
           </p>
           <p>
             By the way: If you want to use an <code>npm</code> module here, just
-            <code>require</code> it. Electron Fiddle will automatically detect that you
+          &nbsp;<code>require</code> it. Electron Fiddle will automatically detect that you
             requested a module and install it as soon as you run your fiddle.
           </p>
         </>

src/renderer/components/version-select.tsx

@@ -0,0 +1,134 @@
+import { Button, IButtonGroupProps, MenuItem } from '@blueprintjs/core';
+import { ItemPredicate, ItemRenderer, Select } from '@blueprintjs/select';
+import { observer } from 'mobx-react';
+import * as React from 'react';
+
+import { ElectronVersion, ElectronVersionSource, ElectronVersionState } from '../../interfaces';
+import { highlightText } from '../../utils/highlight-text';
+import { AppState } from '../state';
+
+const ElectronVersionSelect = Select.ofType<ElectronVersion>();
+
+/**
+ * Helper method: Returns the <Select /> label for an Electron
+ * version.
+ *
+ * @param {ElectronVersion} { source, state }
+ * @returns {string}
+ */
+export function getItemLabel({ source, state, name }: ElectronVersion): string {
+  let label = '';
+
+  if (source === ElectronVersionSource.local) {
+    label = name || 'Local';
+  } else {
+    if (state === ElectronVersionState.unknown) {
+      label = `Not downloaded`;
+    } else if (state === ElectronVersionState.ready) {
+      label = `Downloaded`;
+    } else if (state === ElectronVersionState.downloading) {
+      label = `Downloading`;
+    }
+  }
+
+  return label;
+}
+
+/**
+ * Helper method: Returns the <Select /> icon for an Electron
+ * version.
+ *
+ * @param {ElectronVersion} { state }
+ * @returns
+ */
+export function getItemIcon({ state }: ElectronVersion) {
+  return state === 'ready'
+    ? 'saved'
+    : state === 'downloading' ? 'cloud-download' : 'cloud';
+}
+
+/**
+ * Helper method: Returns the <Select /> predicate for an Electron
+ * version.
+ *
+ * @param {string} query
+ * @param {ElectronVersion} { version }
+ * @returns
+ */
+export const filterItem: ItemPredicate<ElectronVersion> = (query, { version }) => {
+  return version.toLowerCase().includes(query.toLowerCase());
+};
+
+/**
+ * Helper method: Returns the <Select /> <MenuItem /> for Electron
+ * versions.
+ *
+ * @param {ElectronVersion} item
+ * @param {IItemRendererProps} { handleClick, modifiers, query }
+ * @returns
+ */
+export const renderItem: ItemRenderer<ElectronVersion> = (item, { handleClick, modifiers, query }) => {
+  if (!modifiers.matchesPredicate) {
+    return null;
+  }
+
+  return (
+    <MenuItem
+      active={modifiers.active}
+      disabled={modifiers.disabled}
+      text={highlightText(item.version, query)}
+      key={item.version}
+      onClick={handleClick}
+      label={getItemLabel(item)}
+      icon={getItemIcon(item)}
+    />
+  );
+};
+
+export interface VersionSelectState {
+  value: string;
+}
+
+export interface VersionSelectProps {
+  appState: AppState;
+  disabled?: boolean;
+  currentVersion: ElectronVersion;
+  onVersionSelect: (version: ElectronVersion) => void;
+  buttonGroupProps?: IButtonGroupProps;
+  itemDisabled?: keyof ElectronVersion | ((item: ElectronVersion, index: number) => boolean);
+}
+
+/**
+ * A dropdown allowing the selection of Electron versions. The actual
+ * download is managed in the state.
+ *
+ * @class VersionSelect
+ * @extends {React.Component<VersionSelectProps, VersionSelectState>}
+ */
+@observer
+export class VersionSelect extends React.Component<VersionSelectProps, VersionSelectState> {
+  public render() {
+    const { currentVersion, itemDisabled } = this.props;
+    const { version } = currentVersion;
+
+    return (
+      <ElectronVersionSelect
+        filterable={true}
+        items={this.props.appState.versionsToShow}
+        itemRenderer={renderItem}
+        itemPredicate={filterItem}
+        itemDisabled={itemDisabled}
+        onItemSelect={this.props.onVersionSelect}
+        noResults={<MenuItem disabled={true} text='No results.' />}
+        disabled={!!this.props.disabled}
+      >
+        <Button
+          className='version-chooser'
+          text={`Electron v${version}`}
+          icon={getItemIcon(currentVersion)}
+          disabled={!!this.props.disabled}
+        />
+      </ElectronVersionSelect>
+    );
+  }
+}

src/renderer/constants.ts

@@ -1,5 +1,29 @@
 import { remote } from 'electron';
 import * as path from 'path';
+import { MosaicNode } from 'react-mosaic-component';
+
+import { EditorId, MosaicId } from '../interfaces';
+import { EditorBackup } from '../utils/editor-backup';
+
+// Reminder: When testing, this file is mocked in tests/setup.js
 
 export const USER_DATA_PATH = remote.app.getPath('userData');
 export const CONFIG_PATH = path.join(remote.app.getPath('home'), '.electron-fiddle');
+
+export const DEFAULT_MOSAIC_ARRANGEMENT: MosaicNode<MosaicId> = {
+  direction: 'row',
+  first: EditorId.main,
+  second: {
+    direction: 'column',
+    first: EditorId.renderer,
+    second: EditorId.html,
+  }
+};
+
+export const DEFAULT_CLOSED_PANELS: Partial<Record<MosaicId, EditorBackup | true>> = {
+  docsDemo: true,
+  preload: {}
+};
+
+export const ELECTRON_ORG = 'electron';
+export const ELECTRON_REPO = 'electron';

src/renderer/content.ts

@@ -1,32 +1,28 @@
-export const enum ContentNames {
-  HTML = 'html',
-  RENDERER = 'renderer',
-  MAIN = 'main'
-}
+import { EditorId } from '../interfaces';
 
 /**
  * Returns expected content for a given name.
  *
  * @export
- * @param {ContentNames} name
+ * @param {EditorId} name
  * @param {string} [version]
  * @returns {Promise<string>}
  */
 export async function getContent(
-  name: ContentNames,
-  version?: string
+  name: EditorId,
+  version?: string,
 ): Promise<string> {
-  if (name === ContentNames.HTML) {
+  if (name === EditorId.html) {
     return (await import('../content/html')).html;
   }
 
-  if (name === ContentNames.RENDERER) {
+  if (name === EditorId.renderer) {
     return (await import('../content/renderer')).renderer;
   }
 
-  if (name === ContentNames.MAIN) {
+  if (name === EditorId.main) {
     // We currently only distinguish between loadFile
-    // and loadURL. Todo: Properly version the quick-start.
+    // and loadURL. TODO: Properly version the quick-start.
     if (version && version.startsWith('1.')) {
       return (await import('../content/main-1-x-x')).main;
     }
@@ -40,18 +36,18 @@ export async function getContent(
 /**
  * Did the content change?
  *
- * @param {ContentNames} name
+ * @param {EditorId} name
  * @returns {Promise<boolean>}
  */
-export async function isContentUnchanged(name: ContentNames): Promise<boolean> {
+export async function isContentUnchanged(name: EditorId): Promise<boolean> {
   if (!window.ElectronFiddle || !window.ElectronFiddle.app) return false;
 
-  const values = await window.ElectronFiddle.app.getValues({ include: false });
+  const values = await window.ElectronFiddle.app.getEditorValues({ include: false });
 
   // Handle main case, which needs to check both possible versions
-  if (name === ContentNames.MAIN) {
-    const isChanged1x = await getContent(ContentNames.MAIN, '1.0') === values.main;
-    const isChangedOther = await getContent(ContentNames.MAIN) === values.main;
+  if (name === EditorId.main) {
+    const isChanged1x = await getContent(EditorId.main, '1.0') === values.main;
+    const isChangedOther = await getContent(EditorId.main) === values.main;
 
     return isChanged1x || isChangedOther;
   } else {

src/renderer/fetch-types.ts

@@ -2,28 +2,38 @@ import * as fsType from 'fs-extra';
 import * as MonacoType from 'monaco-editor';
 import * as path from 'path';
 
+import { ElectronVersion, ElectronVersionSource } from '../interfaces';
 import { callIn } from '../utils/call-in';
 import { fancyImport } from '../utils/import';
 import { USER_DATA_PATH } from './constants';
 
 const definitionPath = path.join(USER_DATA_PATH, 'electron-typedef');
 
-
 /**
  * Fetch TypeScript definitions for the current version of Electron (online)
  *
  * @param {string} version
  * @returns {Promise<string>}
  */
-export function fetchTypeDefinitions(version: string): Promise<string> {
+export async function fetchTypeDefinitions(version: string): Promise<string> {
   const url = `https://unpkg.com/electron@${version}/electron.d.ts`;
 
-  return window.fetch(url)
-    .then((response) => response.text())
-    .catch((error) => {
-      console.warn(`Fetch Types: Could not fetch definitions`, error);
-      return '';
-    });
+  let text: string;
+  try {
+    const response = await window.fetch(url);
+    text = await response.text();
+  } catch (error) {
+    console.warn(`Fetch Types: Could not fetch definitions`, error);
+    return '';
+  }
+
+  // for invalid packa
+  if (text.includes('Cannot find package')) {
+    console.warn(`Fetch Types: ${text}`);
+    return '';
+  } else {
+    return text;
+  }
 }
 
 /**
@@ -48,27 +58,25 @@ export async function getOfflineTypeDefinitions(version: string): Promise<boolea
 }
 
 /**
- * Get TypeScript defintions for a version of Electron. If none can't be
+ * Get TypeScript definitions for a version of Electron. If none can be
  * found, returns null.
  *
  * @param {string} version
  * @returns {void}
  */
-export async function getTypeDefinitions(version: string): Promise<string | null> {
+export async function getDownloadedVersionTypeDefs(version: ElectronVersion): Promise<string | null> {
   const fs = await fancyImport<typeof fsType>('fs-extra');
-  await fs.mkdirp(definitionPath);
+    await fs.mkdirp(definitionPath);
+    const offlinePath = getOfflineTypeDefinitionPath(version.version);
 
-  const offlinePath = getOfflineTypeDefinitionPath(version);
-
-  if (await getOfflineTypeDefinitions(version)) {
+  if (await getOfflineTypeDefinitions(version.version)) {
     try {
       return await fs.readFile(offlinePath, 'utf-8');
     } catch (error) {
       return null;
     }
   } else {
-    const typeDefs = await fetchTypeDefinitions(version);
-
+    const typeDefs = await fetchTypeDefinitions(version.version);
     if (typeDefs && typeDefs.length > 0) {
       try {
         await fs.outputFile(offlinePath, typeDefs);
@@ -79,17 +87,27 @@ export async function getTypeDefinitions(version: string): Promise<string | null
         return typeDefs;
       }
     }
-
     return null;
   }
 }
 
+export async function getLocalVersionTypeDefs(version: ElectronVersion) {
+  if (version.source === ElectronVersionSource.local && !!version.localPath) {
+    const fs = await fancyImport<typeof fsType>('fs-extra');
+    const typesPath = getLocalTypePathForVersion(version);
+    if (!!typesPath && fs.existsSync(typesPath)) {
+      return fs.readFile(typesPath, 'utf-8');
+    }
+  }
+  return null;
+}
+
 /**
  * Tries to update the editor with type definitions.
  *
  * @param {string} version
  */
-export async function updateEditorTypeDefinitions(version: string, i: number = 0): Promise<void> {
+export async function updateEditorTypeDefinitions(version: ElectronVersion, i: number = 0): Promise<void> {
   const defer = async (): Promise<void> => {
     if (i > 10) {
       console.warn(`Fetch Types: Failed, dependencies do not exist`);
@@ -106,17 +124,36 @@ export async function updateEditorTypeDefinitions(version: string, i: number = 0
   const { app } = window.ElectronFiddle;
   const monaco: typeof MonacoType = app.monaco!;
   const typeDefDisposable: MonacoType.IDisposable = app.typeDefDisposable!;
-  const typeDefs = await getTypeDefinitions(version);
+
+  const getTypeDefs = (version.source === ElectronVersionSource.local) ?
+    getLocalVersionTypeDefs : getDownloadedVersionTypeDefs;
+
+  const typeDefs = await getTypeDefs(version);
 
   if (typeDefDisposable) {
     typeDefDisposable.dispose();
   }
 
   if (typeDefs) {
-    console.log(`Fetch Types: Updating Monaco types with electron.d.ts@${version}`);
+    console.log(`Fetch Types: Updating Monaco types with electron.d.ts@${version.version}`);
     const disposable = monaco.languages.typescript.javascriptDefaults.addExtraLib(typeDefs);
     window.ElectronFiddle.app.typeDefDisposable = disposable;
   } else {
-    console.log(`Fetch Types: No type definitions for ${version} 😢`);
+    console.log(`Fetch Types: No type definitions for ${version.version} 😢`);
+  }
+}
+
+export function getLocalTypePathForVersion(version: ElectronVersion) {
+  if (version.localPath) {
+    return path.join(
+      version.localPath,
+      'gen',
+      'electron',
+      'tsc',
+      'typings',
+      'electron.d.ts'
+    );
+  } else {
+    return null;
   }
 }

src/renderer/file-manager.ts

@@ -3,9 +3,8 @@ import * as path from 'path';
 
 import { EditorValues, Files, FileTransform } from '../interfaces';
 import { IpcEvents } from '../ipc-events';
-import { INDEX_HTML_NAME, MAIN_JS_NAME, PACKAGE_NAME, RENDERER_JS_NAME } from '../shared-constants';
+import { INDEX_HTML_NAME, MAIN_JS_NAME, PACKAGE_NAME, PRELOAD_JS_NAME, RENDERER_JS_NAME } from '../shared-constants';
 import { DEFAULT_OPTIONS, PackageJsonOptions } from '../utils/get-package';
-import { getTitle } from '../utils/get-title';
 import { fancyImport } from '../utils/import';
 import { ipcRendererManager } from './ipc';
 import { AppState } from './state';
@@ -38,12 +37,12 @@ export class FileManager {
   /**
    * Opens a template.
    *
-   * @param {string} name
+   * @param {string} templateName
    * @memberof FileManager
    */
-  public async openTemplate(name: string) {
-    const values = await getTemplateValues(name);
-    this.setFiddle(values);
+  public async openTemplate(templateName: string) {
+    const editorValues = await getTemplateValues(templateName);
+    await window.ElectronFiddle.app.replaceFiddle(editorValues, {templateName});
   }
 
   /**
@@ -59,33 +58,15 @@ export class FileManager {
 
     // We'll do our best and will likely have to
     // rewrite this once we support multiple files
-    const values: EditorValues = {
+    const editorValues: EditorValues = {
       html: await this.readFile(path.join(filePath, INDEX_HTML_NAME)),
       main: await this.readFile(path.join(filePath, MAIN_JS_NAME)),
       renderer: await this.readFile(path.join(filePath, RENDERER_JS_NAME)),
+      preload: await this.readFile(path.join(filePath, PRELOAD_JS_NAME)),
     };
 
-    this.setFiddle(values);
-  }
 
-  /**
-   * Got values? This method will load them.
-   *
-   * @param {EditorValues} values
-   * @memberof FileManager
-   */
-  public async setFiddle(values: EditorValues, filePath?: string) {
-    this.appState.gistId = '';
-    this.appState.isMyGist = false;
-    this.appState.localPath = filePath || null;
-
-    this.appState.setWarningDialogTexts({
-      label: `Opening this fiddle will replace your unsaved changes. Do you want to proceed?`,
-      ok: 'Yes'
-    });
-
-    await window.ElectronFiddle.app.setValues(values);
-    document.title = getTitle(this.appState);
+    window.ElectronFiddle.app.replaceFiddle(editorValues, {filePath});
   }
 
   /**
@@ -107,7 +88,15 @@ export class FileManager {
       const files = await this.getFiles(undefined, ...transforms);
 
       for (const [fileName, content] of files) {
-        await this.saveFile(path.join(pathToSave, fileName), content);
+        const savePath = path.join(pathToSave, fileName);
+
+        // If the file has content, save it to disk. If there's no
+        // content in the file, remove a file that possibly exists.
+        if (content) {
+          await this.saveFile(savePath, content);
+        } else {
+          await this.removeFile(savePath);
+        }
       }
 
       if (pathToSave !== localPath) {
@@ -130,12 +119,13 @@ export class FileManager {
    */
   public async getFiles(options?: PackageJsonOptions, ...transforms: Array<FileTransform>): Promise<Files> {
     const pOptions = typeof options === 'object' ? options : DEFAULT_OPTIONS;
-    const values = await window.ElectronFiddle.app.getValues(pOptions);
+    const values = await window.ElectronFiddle.app.getEditorValues(pOptions);
     let output: Files = new Map();
 
     output.set(RENDERER_JS_NAME, values.renderer);
     output.set(MAIN_JS_NAME, values.main);
     output.set(INDEX_HTML_NAME, values.html);
+    output.set(PRELOAD_JS_NAME, values.preload);
     output.set(PACKAGE_NAME, values.package!);
 
     for (const transform of transforms) {
@@ -238,4 +228,22 @@ export class FileManager {
       ipcRendererManager.send(IpcEvents.FS_SAVE_FIDDLE_ERROR, [filePath]);
     }
   }
+
+  /**
+   * Safely attempts to remove a file, doesn't crash the app if
+   * it fails.
+   *
+   * @param {string} filePath
+   * @returns {string}
+   * @memberof FileManager
+   */
+  private async removeFile(filePath: string): Promise<void> {
+    try {
+      const fs = await fancyImport<typeof fsType>('fs-extra');
+      return await fs.remove(filePath);
+    } catch (error) {
+      console.log(`FileManager: Could not remove ${filePath}`, error);
+      ipcRendererManager.send(IpcEvents.FS_SAVE_FIDDLE_ERROR, [filePath]);
+    }
+  }
 }

src/renderer/npm.ts

@@ -1,6 +1,8 @@
 import { EditorValues } from '../interfaces';
 import { exec } from '../utils/exec';
 
+const { builtinModules } =  require('module');
+
 export interface NpmOperationOptions {
   dir: string;
 }
@@ -11,12 +13,12 @@ export let isInstalled: boolean | null = null;
 /* perhaps we can expose this to the settings module?*/
 const ignoredModules: Array<string> = [
   'electron',
-  // tslint:disable-next-line:no-submodule-imports
-  ...require('builtin-modules/static')
+  'original-fs',
+  ...builtinModules
 ];
 
 /* regular expression to both match and extract module names */
-const requiregx = /require\(['"](.*?)['"]\)/gm;
+const requiregx = /^.*require\(['"](.*?)['"]\)/gm;
 
 
 /*
@@ -91,8 +93,11 @@ export function findModules(input: string): Array<string> {
   /* grab all global require matches in the text */
   // tslint:disable-next-line:no-conditional-assignment
   while (match = (requiregx.exec(input) || null)) {
-    const mod = match[1];
-    modules.push(mod);
+    // ensure commented-out requires aren't downloaded
+    if (!match[0].startsWith('//')) {
+      const mod = match[1];
+      modules.push(mod);
+    }
   }
 
   /* map and reduce */

src/renderer/remote-loader.ts

@@ -0,0 +1,266 @@
+import * as Octokit from '@octokit/rest';
+import { when } from 'mobx';
+import { EditorId, EditorValues, GenericDialogType } from '../interfaces';
+import { INDEX_HTML_NAME, MAIN_JS_NAME, PRELOAD_JS_NAME, RENDERER_JS_NAME } from '../shared-constants';
+import { getOctokit } from '../utils/octokit';
+import { sortedElectronMap } from '../utils/sorted-electron-map';
+import { ELECTRON_ORG, ELECTRON_REPO } from './constants';
+import { getContent } from './content';
+import { AppState } from './state';
+import { ElectronReleaseChannel, getReleaseChannel } from './versions';
+
+export class RemoteLoader {
+  constructor(private readonly appState: AppState) {
+    this.loadFiddleFromElectronExample.bind(this);
+    this.loadFiddleFromGist.bind(this);
+    this.verifyRemoteLoad.bind(this);
+    this.verifyReleaseChannelEnabled.bind(this);
+    this.fetchExampleAndLoad.bind(this);
+    this.fetchGistAndLoad.bind(this);
+    this.setElectronVersionWithRef.bind(this);
+    this.getPackageVersionFromRef.bind(this);
+    this.handleLoadingSuccess.bind(this);
+    this.handleLoadingFailed.bind(this);
+  }
+
+  public async loadFiddleFromElectronExample(_: any, exampleInfo: { path: string; ref: string }) {
+    console.log(`Loading fiddle from Electron example`, _, exampleInfo);
+    const {path, ref} = exampleInfo;
+    const prettyName = path.replace('docs/fiddles/', '');
+    const ok = await this.verifyRemoteLoad(`'${prettyName}' example from the Electron docs for version ${ref}`);
+    if (!ok) return;
+
+    this.fetchExampleAndLoad(ref, path);
+  }
+
+  public async loadFiddleFromGist(_: any, gistInfo: { id: string }) {
+    const {id} = gistInfo;
+    const ok = await this.verifyRemoteLoad(`gist`);
+    if (!ok) return;
+
+    this.fetchGistAndLoad(id);
+  }
+
+  public async fetchExampleAndLoad(ref: string, path: string): Promise<boolean> {
+    try {
+      const octo = await getOctokit(this.appState);
+
+      const folder = await octo.repos.getContents({
+        owner: ELECTRON_REPO,
+        repo: ELECTRON_ORG,
+        ref,
+        path,
+      });
+
+      const ok = await this.setElectronVersionWithRef(ref);
+      if (!ok) return false;
+
+      const values = {
+        html: await getContent(EditorId.html, this.appState.version),
+        renderer: await getContent(EditorId.renderer, this.appState.version),
+        main: await getContent(EditorId.main, this.appState.version),
+        preload: await getContent(EditorId.preload, this.appState.version),
+      };
+
+      const loaders: Array<Promise<void>> = [];
+      if (!Array.isArray(folder.data)) {
+        throw new Error('The example Fiddle tried to launch is not a valid Electron example');
+      }
+
+      for (const child of folder.data) {
+        if (!child.download_url) {
+          console.warn(`Could not find download_url for ${child.name}`);
+          continue;
+        }
+
+        switch (child.name) {
+          case MAIN_JS_NAME:
+            loaders.push(fetch(child.download_url)
+              .then((r) => r.text()).then((t) => { values.main = t; })
+            );
+
+            break;
+          case INDEX_HTML_NAME:
+            loaders.push(fetch(child.download_url)
+              .then((r) => r.text()).then((t) => { values.html = t; })
+            );
+
+            break;
+          case RENDERER_JS_NAME:
+            loaders.push(fetch(child.download_url)
+              .then((r) => r.text()).then((t) => { values.renderer = t; })
+            );
+
+            break;
+
+          case PRELOAD_JS_NAME:
+            loaders.push(fetch(child.download_url)
+              .then((r) => r.text()).then((t) => { values.preload = t; })
+            );
+
+            break;
+          default:
+            break;
+        }
+      }
+
+      await Promise.all(loaders);
+
+      return this.handleLoadingSuccess(values, '');
+    } catch (error) {
+      return this.handleLoadingFailed(error);
+    }
+  }
+
+  /**
+   * Get data from a gist. If it doesn't exist, return an empty string.
+   *
+   * @param {Octokit.Response<Octokit.GistsGetResponse>} gist
+   * @param {string} name
+   * @returns {string}
+   * @memberof RemoteLoader
+   */
+  public getContentOrEmpty(gist: Octokit.Response<Octokit.GistsGetResponse>, name: string): string {
+    try {
+      return gist.data.files[name].content;
+    } catch (error) {
+      return '';
+    }
+  }
+
+  /**
+   * Load a fiddle
+   *
+   * @returns {Promise<boolean>}
+   * @memberof RemoteLoader
+   */
+  public async fetchGistAndLoad(gistId: string): Promise<boolean> {
+    try {
+      const octo = await getOctokit(this.appState);
+      const gist = await octo.gists.get({ gist_id: gistId });
+
+      return this.handleLoadingSuccess({
+        html: this.getContentOrEmpty(gist, INDEX_HTML_NAME),
+        main: this.getContentOrEmpty(gist, MAIN_JS_NAME),
+        renderer: this.getContentOrEmpty(gist, RENDERER_JS_NAME),
+        preload: this.getContentOrEmpty(gist, PRELOAD_JS_NAME)
+      }, gistId);
+    } catch (error) {
+      return this.handleLoadingFailed(error);
+    }
+  }
+
+  public async setElectronVersionWithRef(ref: string): Promise<boolean> {
+    const version = await this.getPackageVersionFromRef(ref);
+
+    const supportedVersions = sortedElectronMap(this.appState.versions, (k) => k);
+    if (!supportedVersions.includes(version)) {
+      this.handleLoadingFailed(new Error('Version of Electron in example not supported'));
+      return false;
+    }
+
+    // check if version is part of release channel
+    const versionReleaseChannel: ElectronReleaseChannel = getReleaseChannel(version);
+
+    if (!this.appState.channelsToShow.includes(versionReleaseChannel)) {
+      const ok = await this.verifyReleaseChannelEnabled(versionReleaseChannel);
+      if (!ok) return false;
+
+      this.appState.channelsToShow.push(versionReleaseChannel);
+    }
+
+    this.appState.setVersion(version);
+    return true;
+  }
+
+  public async getPackageVersionFromRef(ref: string): Promise<string> {
+    const octo = await getOctokit(this.appState);
+    const { data: packageJsonData } = await octo.repos.getContents({
+      owner: ELECTRON_ORG,
+      repo: ELECTRON_REPO,
+      ref,
+      path: 'package.json'
+    });
+
+    if (!Array.isArray(packageJsonData) && !!packageJsonData.content) {
+      const packageJsonString = Buffer.from(packageJsonData.content, 'base64').toString('utf8');
+      const { version } = JSON.parse(packageJsonString);
+      return version;
+    } else {
+      console.error(`getPackageVersionFromRef: Received unexpected response from GitHub, could not parse version`, {
+        packageJsonData
+      });
+
+      return '0.0.0';
+    }
+  }
+
+  /**
+   * Verifies from the user that we should be loading this fiddle
+   *
+   * @param what What are we loading from (gist, example, etc.)
+   */
+  public async verifyRemoteLoad(what: string): Promise<boolean> {
+    this.appState.setGenericDialogOptions({
+      type: GenericDialogType.confirm,
+      label: `Are you sure you want to load this ${what}? Only load and run it if you trust the source.`
+    });
+    this.appState.isGenericDialogShowing = true;
+    await when(() => !this.appState.isGenericDialogShowing);
+
+    return !!this.appState.genericDialogLastResult;
+  }
+
+  public async verifyReleaseChannelEnabled(channel: string): Promise<boolean> {
+    this.appState.setGenericDialogOptions({
+      type: GenericDialogType.warning,
+      label: `You're loading an example with a version of Electron with an unincluded release
+              channel (${channel}). Do you want to enable the release channel to load the
+              version of Electron from the example?`
+    });
+    this.appState.isGenericDialogShowing = true;
+    await when(() => !this.appState.isGenericDialogShowing);
+
+    return !!this.appState.genericDialogLastResult;
+  }
+
+  /**
+   * Loading a fiddle from GitHub succeeded, let's move on.
+   *
+   * @param {Partial<EditorValues>} values
+   * @param {string} gistId
+   * @returns {boolean}
+   */
+  private async handleLoadingSuccess(values: Partial<EditorValues>, gistId: string): Promise<boolean> {
+    await window.ElectronFiddle.app.replaceFiddle(values, {gistId});
+    return true;
+  }
+
+  /**
+   * Loading a fiddle from GitHub failed - this method handles this case
+   * gracefully.
+   *
+   * @param {Error} error
+   * @returns {boolean}
+   */
+  private handleLoadingFailed(error: Error): false {
+    if (navigator.onLine) {
+      this.appState.setGenericDialogOptions({
+        type: GenericDialogType.warning,
+        label: `Loading the fiddle failed: ${error}`,
+        cancel: undefined
+      });
+    } else {
+      this.appState.setGenericDialogOptions({
+        type: GenericDialogType.warning,
+        label: `Loading the fiddle failed. Your computer seems to be offline. Error: ${error}`,
+        cancel: undefined
+      });
+    }
+
+    this.appState.toggleGenericDialog();
+
+    console.warn(`Loading Fiddle failed`, error);
+    return false;
+  }
+}

src/renderer/runner.ts

@@ -37,14 +37,17 @@ export class Runner {
    * @returns {Promise<boolean>}
    */
   public async run(): Promise<boolean> {
-    const { fileManager, getValues } = window.ElectronFiddle.app;
+    const { fileManager, getEditorValues } = window.ElectronFiddle.app;
     const options = { includeDependencies: false, includeElectron: false };
     const { binaryManager, currentElectronVersion } = this.appState;
     const { version, localPath } = currentElectronVersion;
 
+    if (this.appState.isClearingConsoleOnRun) {
+      this.appState.clearConsole();
+    }
     this.appState.isConsoleShowing = true;
 
-    const values = await getValues(options);
+    const values = await getEditorValues(options);
     const dir = await this.saveToTemp(options);
 
     if (!dir) return false;
@@ -181,12 +184,24 @@ export class Runner {
     const binaryPath = binaryManager.getElectronBinaryPath(version, localPath);
     console.log(`Runner: Binary ${binaryPath} ready, launching`);
 
-    this.child = spawn(binaryPath, [ dir, '--inspect' ]);
+    const env = { ...process.env };
+    if (this.appState.isEnablingElectronLogging) {
+      env.ELECTRON_ENABLE_LOGGING = 'true';
+      env.ELECTRON_ENABLE_STACK_DUMPING = 'true';
+    } else {
+      delete env.ELECTRON_ENABLE_LOGGING;
+      delete env.ELECTRON_ENABLE_STACK_DUMPING;
+    }
+
+    // Add user-specified cli flags if any have been set.
+    const options = [ dir, '--inspect' ].concat(this.appState.executionFlags);
+
+    this.child = spawn(binaryPath, options, { cwd: dir, env });
     this.appState.isRunning = true;
     pushOutput(`Electron v${version} started.`);
 
-    this.child.stdout.on('data', (data) => pushOutput(data, { bypassBuffer: false }));
-    this.child.stderr.on('data', (data) => pushOutput(data, { bypassBuffer: false }));
+    this.child.stdout!.on('data', (data) => pushOutput(data, { bypassBuffer: false }));
+    this.child.stderr!.on('data', (data) => pushOutput(data, { bypassBuffer: false }));
     this.child.on('close', async (code) => {
       const withCode = typeof code === 'number'
         ? ` with code ${code.toString()}.`

src/renderer/state.ts

@@ -1,28 +1,44 @@
+import * as fsType from 'fs-extra';
 import { action, autorun, computed, observable, when } from 'mobx';
+import { MosaicNode } from 'react-mosaic-component';
 
 import {
+  ALL_MOSAICS,
+  DocsDemoPage,
+  EditorId,
   ElectronVersion,
   ElectronVersionSource,
   ElectronVersionState,
+  GenericDialogOptions,
+  GenericDialogType,
+  MosaicId,
   NpmVersion,
   OutputEntry,
-  OutputOptions,
-  WarningDialogTexts
+  OutputOptions
 } from '../interfaces';
 import { IpcEvents } from '../ipc-events';
 import { arrayToStringMap } from '../utils/array-to-stringmap';
+import { EditorBackup, getEditorBackup } from '../utils/editor-backup';
+import { createMosaicArrangement, getVisibleMosaics } from '../utils/editors-mosaic-arrangement';
 import { getName } from '../utils/get-title';
+import { fancyImport } from '../utils/import';
 import { normalizeVersion } from '../utils/normalize-version';
+import { isEditorBackup, isEditorId, isPanelId } from '../utils/type-checks';
 import { BinaryManager } from './binary';
-import { ContentNames, getContent, isContentUnchanged } from './content';
-import { updateEditorTypeDefinitions } from './fetch-types';
+import { Bisector } from './bisect';
+import { DEFAULT_CLOSED_PANELS, DEFAULT_MOSAIC_ARRANGEMENT } from './constants';
+import { getContent, isContentUnchanged } from './content';
+import { getLocalTypePathForVersion, updateEditorTypeDefinitions } from './fetch-types';
 import { ipcRendererManager } from './ipc';
 import { activateTheme } from './themes';
+
+import { sortedElectronMap } from '../utils/sorted-electron-map';
 import {
   addLocalVersion,
   ElectronReleaseChannel,
   getDefaultVersion,
   getElectronVersions,
+  getReleaseChannel,
   getUpdatedElectronVersions,
   saveLocalVersions
 } from './versions';
@@ -59,33 +75,52 @@ export class AppState {
   @observable public gitHubLogin: string | null = localStorage.getItem('gitHubLogin');
   @observable public gitHubToken: string | null = localStorage.getItem('gitHubToken') || null;
   @observable public gitHubPublishAsPublic: boolean = !!this.retrieve('gitHubPublishAsPublic');
-  @observable public versionsToShow: Array<ElectronReleaseChannel> =
-    this.retrieve('versionsToShow') as Array<ElectronReleaseChannel>
-      || [ ElectronReleaseChannel.stable, ElectronReleaseChannel.beta ];
+  @observable public channelsToShow: Array<ElectronReleaseChannel> =
+    this.retrieve('channelsToShow') as Array<ElectronReleaseChannel>
+    || [ElectronReleaseChannel.stable, ElectronReleaseChannel.beta];
+  @observable public statesToShow: Array<ElectronVersionState> =
+    this.retrieve('statesToShow') as Array<ElectronVersionState>
+    || [ElectronVersionState.downloading, ElectronVersionState.ready, ElectronVersionState.unknown];
   @observable public isKeepingUserDataDirs: boolean = !!this.retrieve('isKeepingUserDataDirs');
-
-  @observable public binaryManager: BinaryManager = new BinaryManager();
+  @observable public isEnablingElectronLogging: boolean = !!this.retrieve('isEnablingElectronLogging');
+  @observable public isClearingConsoleOnRun: boolean = !!this.retrieve('isClearingConsoleOnRun');
+  @observable public executionFlags: Array<string> =
+    this.retrieve('executionFlags') as Array<string> === null ?
+    [] : this.retrieve('executionFlags') as Array<string>;
 
   // -- Various session-only state ------------------
   @observable public gistId: string = '';
-  @observable public isMyGist: boolean = false;
   @observable public versions: Record<string, ElectronVersion> = arrayToStringMap(knownVersions);
   @observable public output: Array<OutputEntry> = [];
-  @observable public localPath: string | null = null;
-  @observable public isUpdatingElectronVersions = false;
-  @observable public warningDialogTexts = { label: '', ok: 'Okay', cancel: 'Cancel' };
-  @observable public warningDialogLastResult: boolean | null = null;
-  @observable public isRunning = false;
+  @observable public localPath: string | undefined;
+  @observable public genericDialogOptions = { type: GenericDialogType.warning, label: '', ok: 'Okay', cancel: 'Cancel' };
+  @observable public genericDialogLastResult: boolean | null = null;
+  @observable public mosaicArrangement: MosaicNode<MosaicId> | null = DEFAULT_MOSAIC_ARRANGEMENT;
+  @observable public templateName: string | undefined;
+  @observable public currentDocsDemoPage: DocsDemoPage = DocsDemoPage.DEFAULT;
+  @observable public localTypeWatcher: fsType.FSWatcher | undefined;
+  @observable public binaryManager: BinaryManager = new BinaryManager();
+  @observable public Bisector: Bisector | undefined;
+
+  @observable public isPublishing: boolean = false;
+  @observable public isRunning: boolean = false;
+  @observable public isUnsaved: boolean = false;
+  @observable public isUpdatingElectronVersions: boolean = false;
 
   // -- Various "isShowing" settings ------------------
+  @observable public isBisectCommandShowing: boolean;
   @observable public isConsoleShowing: boolean = false;
   @observable public isTokenDialogShowing: boolean = false;
-  @observable public isWarningDialogShowing: boolean = false;
+  @observable public isGenericDialogShowing: boolean = false;
   @observable public isSettingsShowing: boolean = false;
-  @observable public isUnsaved: boolean = false;
+  @observable public isBisectDialogShowing: boolean = false;
   @observable public isAddVersionDialogShowing: boolean = false;
+  @observable public isThemeDialogShowing: boolean = false;
   @observable public isTourShowing: boolean = !localStorage.getItem('hasShownTour');
 
+  // -- Editor Values stored when we close the editor ------------------
+  @observable public closedPanels: Partial<Record<MosaicId, EditorBackup | true>> = DEFAULT_CLOSED_PANELS;
+
   private outputBuffer: string = '';
   private name: string;
 
@@ -98,41 +133,60 @@ export class AppState {
     this.setVersion = this.setVersion.bind(this);
     this.showTour = this.showTour.bind(this);
     this.signOutGitHub = this.signOutGitHub.bind(this);
+    this.toggleBisectCommands = this.toggleBisectCommands.bind(this);
     this.toggleAuthDialog = this.toggleAuthDialog.bind(this);
     this.toggleConsole = this.toggleConsole.bind(this);
+    this.clearConsole = this.clearConsole.bind(this);
     this.toggleSettings = this.toggleSettings.bind(this);
+    this.toggleBisectDialog = this.toggleBisectDialog.bind(this);
     this.updateElectronVersions = this.updateElectronVersions.bind(this);
 
     ipcRendererManager.on(IpcEvents.OPEN_SETTINGS, this.toggleSettings);
     ipcRendererManager.on(IpcEvents.SHOW_WELCOME_TOUR, this.showTour);
+    ipcRendererManager.on(IpcEvents.CLEAR_CONSOLE, this.clearConsole);
+    ipcRendererManager.on(IpcEvents.BISECT_COMMANDS_TOGGLE, this.toggleBisectCommands);
 
     // Setup auto-runs
     autorun(() => this.save('theme', this.theme));
+    autorun(() => this.save('isClearingConsoleOnRun', this.isClearingConsoleOnRun));
     autorun(() => this.save('gitHubAvatarUrl', this.gitHubAvatarUrl));
     autorun(() => this.save('gitHubLogin', this.gitHubLogin));
     autorun(() => this.save('gitHubName', this.gitHubName));
     autorun(() => this.save('gitHubToken', this.gitHubToken));
     autorun(() => this.save('gitHubPublishAsPublic', this.gitHubPublishAsPublic));
     autorun(() => this.save('isKeepingUserDataDirs', this.isKeepingUserDataDirs));
+    autorun(() => this.save('isEnablingElectronLogging', this.isEnablingElectronLogging));
+    autorun(() => this.save('executionFlags', this.executionFlags));
     autorun(() => this.save('version', this.version));
-    autorun(() => this.save('versionsToShow', this.versionsToShow));
+    autorun(() => this.save('channelsToShow', this.channelsToShow));
+    autorun(() => this.save('statesToShow', this.statesToShow));
 
     autorun(() => {
       if (this.isUnsaved) {
         window.onbeforeunload = () => {
-          this.setWarningDialogTexts({
+          this.setGenericDialogOptions({
+            type: GenericDialogType.warning,
             label: `The current Fiddle is unsaved. Do you want to exit anyway?`,
             ok: 'Quit'
           });
 
-          this.isWarningDialogShowing = true;
+          this.isGenericDialogShowing = true;
 
           // We'll wait until the warning dialog was closed
-          when(() => !this.isWarningDialogShowing).then(() => {
+          when(() => !this.isGenericDialogShowing).then(() => {
             // The user confirmed, let's close for real.
-            if (this.warningDialogLastResult) {
+            if (this.genericDialogLastResult) {
               window.onbeforeunload = null;
-              window.close();
+
+              // Should we just close or quit?
+              const remote = require('electron').remote;
+              const isQuitting = remote.getGlobal('isQuitting');
+
+              if (isQuitting) {
+                remote.app.quit();
+              } else {
+                window.close();
+              }
             }
           });
 
@@ -162,6 +216,31 @@ export class AppState {
     }
   }
 
+  /**
+   * Returns an array of Electron versions to show given the
+   * current settings for states and channels to display
+   */
+  @computed get versionsToShow(): Array<ElectronVersion> {
+    return sortedElectronMap<ElectronVersion>(this.versions, (_key, item) => item)
+      .filter((item) => {
+        if (!item) {
+          return false;
+        }
+
+        // Check if we want to show the version
+        if (!this.channelsToShow.includes(getReleaseChannel(item))) {
+          return false;
+        }
+
+        // Check if we want to show the state
+        if (!this.statesToShow.includes(item.state)) {
+          return false;
+        }
+
+        return true;
+      });
+  }
+
   /**
    * Update the Electron versions: First, fetch them from GitHub,
    * then update their respective downloaded state.
@@ -194,22 +273,41 @@ export class AppState {
     this.isConsoleShowing = !this.isConsoleShowing;
   }
 
+  @action public clearConsole() {
+    this.output = [];
+  }
+
+  @action public toggleBisectCommands() {
+    // guard against hiding the commands when executing a bisect
+    if (!this.Bisector && !this.isBisectDialogShowing) {
+      this.isBisectCommandShowing = !this.isBisectCommandShowing;
+    }
+  }
+
   @action public toggleAddVersionDialog() {
     this.isAddVersionDialogShowing = !this.isAddVersionDialogShowing;
   }
 
+  @action public toggleAddMonacoThemeDialog() {
+    this.isThemeDialogShowing = !this.isThemeDialogShowing;
+  }
+
   @action public toggleAuthDialog() {
     this.isTokenDialogShowing = !this.isTokenDialogShowing;
   }
 
-  @action public toogleWarningDialog() {
-    this.isWarningDialogShowing = !this.isWarningDialogShowing;
+  @action public toggleGenericDialog() {
+    this.isGenericDialogShowing = !this.isGenericDialogShowing;
 
-    if (this.isWarningDialogShowing) {
-      this.warningDialogLastResult = null;
+    if (this.isGenericDialogShowing) {
+      this.genericDialogLastResult = null;
     }
   }
 
+  @action public toggleBisectDialog() {
+    this.isBisectDialogShowing = !this.isBisectDialogShowing;
+  }
+
   @action public toggleSettings() {
     // We usually don't lose editor focus,
     // so you can still type. Let's force-blur.
@@ -235,11 +333,12 @@ export class AppState {
     window.ElectronFiddle.app.setupTheme();
   }
 
-  @action public setWarningDialogTexts(input: WarningDialogTexts) {
-    this.warningDialogTexts = {
+  @action public setGenericDialogOptions(opts: GenericDialogOptions) {
+    this.genericDialogOptions = {
+      type: GenericDialogType.warning,
       ok: 'Okay',
       cancel: 'Cancel',
-      ...input
+      ...opts
     };
   }
 
@@ -250,12 +349,12 @@ export class AppState {
     this.updateDownloadedVersionState();
   }
 
- /**
-  * Remove a version of Electron
-  *
-  * @param {string} input
-  * @returns {Promise<void>}
-  */
+  /**
+   * Remove a version of Electron
+   *
+   * @param {string} input
+   * @returns {Promise<void>}
+   */
   @action public async removeVersion(input: string) {
     const version = normalizeVersion(input);
     const release = this.versions[version];
@@ -289,12 +388,12 @@ export class AppState {
     this.updateDownloadedVersionState();
   }
 
- /**
-  * Download a version of Electron.
-  *
-  * @param {string} input
-  * @returns {Promise<void>}
-  */
+  /**
+   * Download a version of Electron.
+   *
+   * @param {string} input
+   * @returns {Promise<void>}
+   */
   @action public async downloadVersion(input: string) {
     const version = normalizeVersion(input);
     console.log(`State: Downloading Electron ${version}`);
@@ -318,12 +417,12 @@ export class AppState {
     }
   }
 
- /**
-  * Select a version of Electron (and download it if necessary).
-  *
-  * @param {string} input
-  * @returns {Promise<void>}
-  */
+  /**
+   * Select a version of Electron (and download it if necessary).
+   *
+   * @param {string} input
+   * @returns {Promise<void>}
+   */
   @action public async setVersion(input: string) {
     const version = normalizeVersion(input);
 
@@ -339,23 +438,40 @@ export class AppState {
     this.version = version;
 
     // Should we update the editor?
-    if (await isContentUnchanged(ContentNames.MAIN)) {
-      const main = await getContent(ContentNames.MAIN, version);
-      window.ElectronFiddle.app.setValues({ main }, false);
+    if (await isContentUnchanged(EditorId.main)) {
+      const main = await getContent(EditorId.main, version);
+      window.ElectronFiddle.app.setEditorValues({ main });
     }
 
     // Update TypeScript definitions
-    updateEditorTypeDefinitions(version);
+    const versionObject = this.versions[version];
+
+    if (versionObject.source === ElectronVersionSource.local) {
+      const fs = await fancyImport<typeof fsType>('fs-extra');
+      const typePath = getLocalTypePathForVersion(versionObject);
+      console.info(`TypeDefs: Watching file for local version ${version} at path ${typePath}`);
+      this.localTypeWatcher = fs.watch(typePath!, async () => {
+        console.info(`TypeDefs: Noticed file change at ${typePath}. Updating editor typedefs.`);
+        await updateEditorTypeDefinitions(versionObject);
+      });
+    } else {
+      if (!!this.localTypeWatcher) {
+        console.info(`TypeDefs: Switched to downloaded version ${version}. Unwatching local typedefs.`);
+        this.localTypeWatcher.close();
+        this.localTypeWatcher = undefined;
+      }
+    }
+    await updateEditorTypeDefinitions(versionObject);
 
     // Fetch new binaries, maybe?
     await this.downloadVersion(version);
   }
 
- /**
-  * Go and check which versions have already been downloaded.
-  *
-  * @returns {Promise<void>}
-  */
+  /**
+   * Go and check which versions have already been downloaded.
+   *
+   * @returns {Promise<void>}
+   */
   @action public async updateDownloadedVersionState(): Promise<void> {
     const downloadedVersions = await this.binaryManager.getDownloadedVersions();
     const updatedVersions = { ...this.versions };
@@ -394,7 +510,7 @@ export class AppState {
     let strData = data.toString();
     const { isNotPre, bypassBuffer } = options;
 
-    // Todo: This drops the first part of the buffer... is that fully expected?
+    // TODO: This drops the first part of the buffer... is that fully expected?
     if (process.platform === 'win32' && bypassBuffer === false) {
       this.outputBuffer += strData;
       strData = this.outputBuffer;
@@ -435,6 +551,66 @@ export class AppState {
     console.warn(error);
   }
 
+  /**
+   * Sets the editor value for a given editor. Deletes the value after
+   * accessing it.
+   *
+   * @param {EditorId} id
+   */
+  @action public getAndRemoveEditorValueBackup(id: EditorId): EditorBackup | null {
+    const value = this.closedPanels[id];
+
+    if (isEditorBackup(value)) {
+      delete this.closedPanels[id];
+      return value;
+    }
+
+    return null;
+  }
+
+  @action public setVisibleMosaics(visible: Array<MosaicId>) {
+    const currentlyVisible = getVisibleMosaics(this.mosaicArrangement);
+
+    for (const id of ALL_MOSAICS) {
+      if (!visible.includes(id) && currentlyVisible.includes(id)) {
+        this.closedPanels[id] = isEditorId(id)
+          ? getEditorBackup(id)
+          : true;
+      }
+
+      // Remove the backup for panels now. Editors will remove their
+      // backup once the data has been loaded.
+      if (isPanelId(id) && visible.includes(id) && !currentlyVisible.includes(id)) {
+        delete this.closedPanels[id];
+      }
+    }
+
+    const updatedArrangement = createMosaicArrangement(visible);
+    console.log(`State: Setting visible mosaic panels`, visible, updatedArrangement);
+
+    this.mosaicArrangement = updatedArrangement;
+  }
+
+  /**
+   * Hides the panel for a given MosaicId.
+   *
+   * @param {MosaicId} id
+   */
+  @action public hideAndBackupMosaic(id: MosaicId) {
+    const currentlyVisible = getVisibleMosaics(this.mosaicArrangement);
+    this.setVisibleMosaics(currentlyVisible.filter((v) => v !== id));
+  }
+
+  /**
+   * Shows the editor value for a given editor.
+   *
+   * @param {MosaicId} id
+   */
+  @action public showMosaic(id: MosaicId) {
+    const currentlyVisible = getVisibleMosaics(this.mosaicArrangement);
+    this.setVisibleMosaics([...currentlyVisible, id]);
+  }
+
   /**
    * Resets the view, optionally with certain view flags enabled.
    *
@@ -447,6 +623,7 @@ export class AppState {
     this.isTourShowing = false;
     this.isConsoleShowing = false;
     this.isAddVersionDialogShowing = false;
+    this.isThemeDialogShowing = false;
 
     if (additionalOptions) {
       for (const key in additionalOptions) {

src/renderer/templates.ts

@@ -2,12 +2,11 @@ import * as fsExtraType from 'fs-extra';
 import * as pathType from 'path';
 
 import { EditorValues } from '../interfaces';
-import { INDEX_HTML_NAME, MAIN_JS_NAME, RENDERER_JS_NAME } from '../shared-constants';
+import { INDEX_HTML_NAME, MAIN_JS_NAME, PRELOAD_JS_NAME, RENDERER_JS_NAME } from '../shared-constants';
 import { fancyImport } from '../utils/import';
 
 /**
- * Returns expected content for a given name. Currently synchronous,
- * but probably shouldn't be.
+ * Returns expected content for a given name.
  *
  * @param {string} name
  * @returns {Promise<EditorValues>}
@@ -15,8 +14,8 @@ import { fancyImport } from '../utils/import';
 export async function getTemplateValues(name: string): Promise<EditorValues> {
   const path = await fancyImport<typeof pathType>('path');
   const fs = await fancyImport<typeof fsExtraType>('fs-extra');
-
-  const templatePath = path.join(__dirname, '../../static/templates', name.toLowerCase());
+  const templatesPath = path.join(__dirname, '../../static/show-me');
+  const templatePath = path.join(templatesPath, name.toLowerCase());
 
   const getFile = async (fileName: string) => {
     try {
@@ -25,7 +24,15 @@ export async function getTemplateValues(name: string): Promise<EditorValues> {
 
       return content;
     } catch (error) {
-      console.warn(`Could not get template file:`, error);
+      console.warn(`getTemplateValues(): Could not get template file:`, error);
+
+      if (fs.existsSync(templatesPath)) {
+        const contents = fs.readdirSync(templatesPath);
+        console.log(`getTemplateValues(): ${templatesPath} contents:`, contents);
+      } else {
+        console.log(`getTemplateValues(): ${templatesPath} does not exist`);
+      }
+
       return '';
     }
   };
@@ -33,6 +40,7 @@ export async function getTemplateValues(name: string): Promise<EditorValues> {
   return {
     renderer: await getFile(RENDERER_JS_NAME),
     main: await getFile(MAIN_JS_NAME),
-    html: await getFile(INDEX_HTML_NAME)
+    html: await getFile(INDEX_HTML_NAME),
+    preload: await getFile(PRELOAD_JS_NAME)
   };
 }

src/renderer/touch-bar-manager.ts

@@ -0,0 +1,283 @@
+import {
+  remote,
+  TouchBarButtonConstructorOptions,
+  TouchBarScrubberConstructorOptions
+} from 'electron';
+import { autorun } from 'mobx';
+
+import { ElectronVersion, ElectronVersionState } from '../interfaces';
+import { getNiceGreeting } from '../utils/nice-greeting';
+import { sortedElectronMap } from '../utils/sorted-electron-map';
+import { AppState } from './state';
+
+const { TouchBar } = remote;
+const {
+  TouchBarButton,
+  TouchBarScrubber,
+  TouchBarSpacer,
+  TouchBarLabel
+} = TouchBar;
+
+/**
+ * Helper method: Returns an icon (emoji, lol) for an Electron
+ * version.
+ *
+ * @param {Partial<ElectronVersion>} { state }
+ * @returns {string}
+ */
+export function getItemIcon(
+  { state }: Partial<ElectronVersion> = { state: ElectronVersionState.unknown }
+) {
+  return state === 'ready'
+    ? '💾'
+    : state === 'downloading' ? '⏬' : '☁';
+}
+
+export class TouchBarManager {
+  public browserWindow: Electron.BrowserWindow;
+  public consoleBtn: Electron.TouchBarButton;
+  public startStopBtn: Electron.TouchBarButton;
+  public touchBar: Electron.TouchBar;
+  public versionSelector: Electron.TouchBarScrubber;
+  public versionSelectorBtn: Electron.TouchBarButton;
+  public selectedVersion: string = '';
+  public versionSelectorSelectBtn: Electron.TouchBarButton;
+  // Lol have mercy, TS
+  public items: Array<Electron.TouchBarButton
+    | Electron.TouchBarColorPicker
+    | Electron.TouchBarGroup
+    | Electron.TouchBarLabel
+    | Electron.TouchBarPopover
+    | Electron.TouchBarScrubber
+    | Electron.TouchBarSegmentedControl
+    | Electron.TouchBarSlider
+    | Electron.TouchBarSpacer>
+    | undefined;
+
+  constructor(public readonly appState: AppState) {
+    this.selectVersion = this.selectVersion.bind(this);
+    this.updateStartStopBtn = this.updateStartStopBtn.bind(this);
+    this.updateVersionSelectorItems = this.updateVersionSelectorItems.bind(this);
+    this.updateVersionButton = this.updateVersionButton.bind(this);
+
+    this.startStopBtn = new TouchBarButton(this.getStartStopButtonOptions());
+    this.consoleBtn = new TouchBarButton(this.getConsoleButtonOptions());
+    this.versionSelectorBtn = new TouchBarButton(this.getVersionButtonOptions());
+    this.versionSelectorSelectBtn = new TouchBarButton(this.getVersionSelectorSelectButtonOptions());
+    this.versionSelector = new TouchBarScrubber(this.getVersionSelectorOptions());
+
+    this.setupTouchBar();
+  }
+
+  /**
+   * This method is called right after we instantiate the manager. It sets up
+   * autoruns that respond to state changes (like new versions) and also
+   * greets the user with a kind little message.
+   */
+  public setupTouchBar() {
+    // First, the welcome
+    this.setWelcomeItems();
+
+    // Then, go with the intro
+    setTimeout(() => {
+      this.setDefaultItems();
+    }, 4000);
+
+    autorun(this.updateStartStopBtn);
+    autorun(this.updateVersionSelectorItems);
+    autorun(this.updateVersionButton);
+  }
+
+  /**
+   * Whenever run/stop status changes, we'll update it (thanks, mobx)
+   */
+  public updateStartStopBtn() {
+    const { label } = this.getStartStopButtonOptions();
+    this.startStopBtn.label = label!;
+  }
+
+  /**
+   * Whenever the electron versions change, we'll update
+   * the items in the scrubber (thanks, mobx)
+   */
+  public updateVersionSelectorItems() {
+    this.versionSelector.items = this.getVersions();
+  }
+
+  /**
+   * Whenever the Electron version changes, update the version button
+   */
+  public updateVersionButton() {
+    const { label } = this.getVersionButtonOptions();
+    this.versionSelectorBtn.label = label!;
+  }
+
+  public getVersions() {
+    return sortedElectronMap(this.appState.versions || {}, (key, version) => ({
+      label: `${getItemIcon(version)} ${key}`,
+    }));
+  }
+
+  /**
+   * Safely set the touch bar on the current window
+   *
+   * @param {Partial<Electron.TouchBarConstructorOptions>} options
+   */
+  public setTouchBar(options: Partial<Electron.TouchBarConstructorOptions>) {
+    try {
+      this.items = options.items;
+      this.touchBar = new TouchBar(options as Electron.TouchBarConstructorOptions);
+      this.browserWindow = this.browserWindow || remote.getCurrentWindow();
+      this.browserWindow.setTouchBar(this.touchBar);
+    } catch (error) {
+      console.warn(`Could not set touch bar`, { error });
+    }
+  }
+
+  /**
+   * A bar that just contains a little welcome message
+   */
+  public setWelcomeItems() {
+    this.setTouchBar({
+      items: [
+        new TouchBarSpacer({ size: 'flexible' }),
+        new TouchBarLabel({ label: getNiceGreeting() }),
+        new TouchBarSpacer({ size: 'flexible' })
+      ]
+    });
+  }
+
+  /**
+   * A bar with the default items
+   */
+  public setDefaultItems() {
+    this.setTouchBar({
+      items: [
+        this.startStopBtn,
+        this.consoleBtn,
+        new TouchBarSpacer({ size: 'flexible' }),
+        this.versionSelectorBtn,
+        new TouchBarSpacer({ size: 'flexible' })
+      ]
+    });
+  }
+
+  /**
+   * A bar that just contains the version scrubber
+   */
+  public setVersionSelectorItems() {
+    this.setTouchBar({
+      items: [
+        this.versionSelector,
+        this.versionSelectorSelectBtn,
+      ],
+      escapeItem: new TouchBarButton(
+        this.getVersionSelectorEscButtonOptions()
+      )
+    });
+  }
+
+  /**
+   * The version selector gets a custom "escape" button that'll
+   * take the user back to the "default" touch bar interface
+   */
+  public getVersionSelectorEscButtonOptions() {
+    return {
+      label: `Back`,
+      click: () => {
+        this.setDefaultItems();
+      }
+    };
+  }
+
+  /**
+   * The version selector also gets a "select" button that'll
+   * commit the selected version
+   */
+  public getVersionSelectorSelectButtonOptions() {
+    return {
+      label: `🎯 Select`,
+      click: () => {
+        if (this.selectedVersion) {
+          this.appState.setVersion(this.selectedVersion);
+        }
+
+        this.setDefaultItems();
+      }
+    };
+  }
+
+  /**
+   * The start button is wired up to launching the current
+   * fiddle.
+   *
+   * @returns {TouchBarButtonConstructorOptions}
+   */
+  public getStartStopButtonOptions(): TouchBarButtonConstructorOptions {
+    const label = this.appState.isRunning
+      ? '🛑 Stop'
+      : '🚀 Run';
+
+    const click = () => this.appState.isRunning
+      ? window.ElectronFiddle.app.runner.stop()
+      : window.ElectronFiddle.app.runner.run();
+
+    return { label, click };
+  }
+
+  /**
+   * The console button is wired up to toggle the console
+   *
+   * @returns {TouchBarButtonConstructorOptions}
+   */
+  public getConsoleButtonOptions(): TouchBarButtonConstructorOptions {
+    const label = '🖥 Console';
+    const click = this.appState.toggleConsole;
+
+    return { label, click };
+  }
+
+  /**
+   *  The version button opens the scrubber, allowing selection
+   *  of a version
+   *
+   * @returns {TouchBarButtonConstructorOptions}
+   */
+  public getVersionButtonOptions(): TouchBarButtonConstructorOptions {
+    const label = `🔖 Electron ${this.appState.version}`;
+    const click = () => this.setVersionSelectorItems();
+
+    return { label, click };
+  }
+
+  /**
+   * Options for the version selection scrubber
+   *
+   * @returns {TouchBarScrubberConstructorOptions}
+   */
+  public getVersionSelectorOptions(
+  ): TouchBarScrubberConstructorOptions {
+    return {
+      select: this.selectVersion,
+      highlight: this.selectVersion,
+      items: [],
+      selectedStyle: 'background',
+      overlayStyle: 'outline',
+      mode: 'free',
+      continuous: true,
+      showArrowButtons: false
+    };
+  }
+
+  /**
+   * Called once the version selection scrubber is closed (
+   * with confirmation)
+   *
+   * @param {number} index
+   */
+  public selectVersion(index: number) {
+    const versions = sortedElectronMap(this.appState.versions || {}, (k) => k);
+
+    this.selectedVersion = versions[index];
+  }
+}

src/renderer/transforms/forge.ts

@@ -15,11 +15,11 @@ export async function forgeTransform(files: Files): Promise<Files> {
 
       // devDependencies
       parsed.devDependencies = parsed.devDependencies || {};
-      parsed.devDependencies['@electron-forge/cli'] = '6.0.0-beta.22';
-      parsed.devDependencies['@electron-forge/maker-deb'] = '6.0.0-beta.22';
-      parsed.devDependencies['@electron-forge/maker-rpm'] = '6.0.0-beta.22';
-      parsed.devDependencies['@electron-forge/maker-squirrel'] = '6.0.0-beta.22';
-      parsed.devDependencies['@electron-forge/maker-zip'] = '6.0.0-beta.22';
+      parsed.devDependencies['@electron-forge/cli'] = '6.0.0-beta.34';
+      parsed.devDependencies['@electron-forge/maker-deb'] = '6.0.0-beta.34';
+      parsed.devDependencies['@electron-forge/maker-rpm'] = '6.0.0-beta.34';
+      parsed.devDependencies['@electron-forge/maker-squirrel'] = '6.0.0-beta.34';
+      parsed.devDependencies['@electron-forge/maker-zip'] = '6.0.0-beta.34';
 
       // Scripts
       parsed.scripts = parsed.scripts || {};

src/renderer/versions.ts

@@ -45,13 +45,14 @@ export function getDefaultVersion(
  * Return the release channel for a given input
  * version.
  *
- * @param {NpmVersion} input
+ * @param {NpmVersion | string} input
  * @returns {ElectronReleaseChannel}
  */
 export function getReleaseChannel(
-  input: NpmVersion
+  input: NpmVersion | string
 ): ElectronReleaseChannel {
-  const tag = input.version || '';
+
+  const tag = (typeof input === 'string') ? input : (input.version || '');
 
   if (tag.includes('beta')) {
     return ElectronReleaseChannel.beta;
@@ -235,13 +236,18 @@ export async function getUpdatedElectronVersions(
  * @returns {Promise<Array<NpmVersion>>}
  */
 export async function fetchVersions() {
-  const response = await window.fetch(`https://registry.npmjs.org/electron`);
-  const data = await response.json();
-  const versions: Record<string, any> = data.versions;
+  const channels = [
+    `https://registry.npmjs.org/electron`,        // stable, beta
+    `https://registry.npmjs.org/electron-nightly` // nightly
+  ];
 
-  const output: Array<NpmVersion> = Object
-    .keys(versions)
-    .map((version) => ({ version }));
+  const output: Array<NpmVersion> = [];
+  for (const channelUrl of channels) {
+    const response = await window.fetch(channelUrl);
+    const data = await response.json();
+    const versions: Record<string, any> = data.versions;
+    output.push(...Object.keys(versions).map((version) => ({ version })));
+  }
 
   if (output && output.length > 0 && isExpectedFormat(output)) {
     console.log(`Fetched new Electron versions (Count: ${output.length})`);

src/shared-constants.ts

@@ -1,4 +1,5 @@
 export const INDEX_HTML_NAME = 'index.html';
 export const MAIN_JS_NAME = 'main.js';
 export const RENDERER_JS_NAME = 'renderer.js';
+export const PRELOAD_JS_NAME = 'preload.js';
 export const PACKAGE_NAME = 'package.json';

src/utils/docs-urls.ts

@@ -0,0 +1,13 @@
+/**
+ * Get all the documentation urls for a given module name.
+ *
+ * @export
+ * @param {string} moduleName
+ */
+export function getDocsUrlForModule(moduleName: string) {
+  return {
+    full: `https://electronjs.org/docs/api/${moduleName}`,
+    repo: `https://github.com/electron/electron/blob/master/docs/api/${moduleName}.md`,
+    short: `electronjs.org/docs/api/${moduleName}`
+  };
+}

src/utils/editor-backup.ts

@@ -0,0 +1,26 @@
+import { editor } from 'monaco-editor';
+
+import { EditorId } from '../interfaces';
+import { getEditorModel } from './editor-model';
+import { getEditorValue } from './editor-value';
+import { getEditorViewState } from './editor-viewstate';
+
+export interface EditorBackup {
+  value?: string;
+  model?: editor.ITextModel | null;
+  viewState?: editor.ICodeEditorViewState | null;
+}
+
+/**
+ * Returns a backup for a given editor
+ *
+ * @param {EditorId} id
+ * @returns {EditorBackup}
+ */
+export function getEditorBackup(id: EditorId): EditorBackup {
+  return {
+    value: getEditorValue(id),
+    model: getEditorModel(id),
+    viewState: getEditorViewState(id)
+  };
+}

src/utils/editor-layout.ts

@@ -3,11 +3,11 @@
  * a debounced version below.
  */
 function _updateEditorLayout() {
-  const { main, renderer, html } = window.ElectronFiddle.editors;
-
-  if (main) main.layout();
-  if (renderer) renderer.layout();
-  if (html) html.layout();
+  Object.keys(window.ElectronFiddle.editors).forEach((key) => {
+    if (window.ElectronFiddle.editors[key]) {
+      window.ElectronFiddle.editors[key].layout();
+    }
+  });
 }
 
 let handle: number;

src/utils/editor-model.ts

@@ -0,0 +1,23 @@
+import { editor } from 'monaco-editor';
+
+import { EditorId } from '../interfaces';
+
+/**
+ * Return the model for a given editor
+ *
+ * @param {EditorId} id
+ * @returns {editor.ITextModel | null}
+ */
+export function getEditorModel(id: EditorId): editor.ITextModel  | null {
+  const { ElectronFiddle: fiddle } = window;
+
+  if (!fiddle) {
+    throw new Error('Fiddle not ready');
+  }
+
+  if (fiddle.editors[id] && fiddle.editors[id]!.getModel) {
+    return fiddle.editors[id]!.getModel();
+  }
+
+  return null;
+}

src/utils/editor-value.ts

@@ -0,0 +1,21 @@
+import { EditorId } from '../interfaces';
+
+/**
+ * Return the value for a given editor
+ *
+ * @param {EditorId} id
+ * @returns {string}
+ */
+export function getEditorValue(id: EditorId): string {
+  const { ElectronFiddle: fiddle } = window;
+
+  if (!fiddle) {
+    throw new Error('Fiddle not ready');
+  }
+
+  if (fiddle.editors[id] && fiddle.editors[id]!.getValue) {
+    return fiddle.editors[id]!.getValue();
+  }
+
+  return '';
+}

src/utils/editor-viewstate.ts

@@ -0,0 +1,24 @@
+import { editor } from 'monaco-editor';
+
+import { EditorId } from '../interfaces';
+
+/**
+ * Returns the view state for a given editor.
+ *
+ * @export
+ * @param {EditorId} id
+ * @returns {(editor.ICodeEditorViewState | null)}
+ */
+export function getEditorViewState(id: EditorId): editor.ICodeEditorViewState | null {
+  const { ElectronFiddle: fiddle } = window;
+
+  if (!fiddle) {
+    throw new Error('Fiddle not ready');
+  }
+
+  if (fiddle.editors[id] && fiddle.editors[id]!.saveViewState) {
+    return fiddle.editors[id]!.saveViewState();
+  }
+
+  return null;
+}

src/utils/editors-mosaic-arrangement.ts

@@ -0,0 +1,57 @@
+import { MosaicDirection, MosaicNode } from 'react-mosaic-component';
+
+import { MosaicId } from '../interfaces';
+
+/**
+ * Create a mosaic arrangement given an array of editor ids.
+ *
+ * @export
+ * @param {Array<MosaicId>} input
+ * @returns {MosaicNode<MosaicId>}
+ */
+export function createMosaicArrangement(
+  input: Array<MosaicId>, direction: MosaicDirection = 'row'
+): MosaicNode<MosaicId> {
+  if (input.length === 1) {
+    return input[0];
+  }
+
+  // This cuts out the first half of input. Input becomes the second half.
+  const secondHalf = [ ...input ];
+  const firstHalf = secondHalf.splice(0, Math.floor(secondHalf.length / 2));
+
+  return {
+    direction,
+    first: createMosaicArrangement(firstHalf, 'column'),
+    second: createMosaicArrangement(secondHalf, 'column')
+  };
+}
+
+/**
+ * Returns an array of visible editors given a mosaic arrangement.
+ *
+ * @export
+ * @param {MosaicNode<MosaicId> | null} input
+ * @returns {Array<MosaicId>}
+ */
+export function getVisibleMosaics(input: MosaicNode<MosaicId> | null): Array<MosaicId> {
+  // Handle the unlikely null case
+  if (!input) return [];
+
+  // Handle the case where only one editor is visible
+  if (typeof input === 'string') {
+    return [ input ];
+  }
+
+  // Handle the other cases (2 - 4)
+  const result = [];
+  for (const node of [ input.first, input.second ]) {
+    if (typeof node === 'string') {
+      result.push(node);
+    } else {
+      result.push(...getVisibleMosaics(node));
+    }
+  }
+
+  return result;
+}

src/utils/nice-greeting.ts

@@ -0,0 +1,25 @@
+import { getRandomNumber } from './random';
+
+/**
+ * Get a random nice greeting
+ *
+ * @export
+ * @returns
+ */
+export function getNiceGreeting() {
+  const greetings = [
+    '👋 Go build a great app',
+    '💖 You got this',
+    `💖 We think you're great`,
+    '🤘 Your app will rock, we know it',
+    '🙇‍♀️ Thanks for trying out Electron & Fiddle',
+    '🐕 Go pet a dog today',
+    '🐈 Go pet a cat today',
+    '💧 Stay hydrated',
+  ];
+
+  const min = 0;
+  const max = greetings.length;
+
+  return greetings[getRandomNumber(min, max)];
+}

src/utils/octokit.ts

@@ -1,15 +1,30 @@
 import * as GitHubType from '@octokit/rest';
+import { AppState } from '../renderer/state';
 
 let _Octokit: typeof GitHubType;
 let _octo: GitHubType;
 
 /**
- * Returns a loaded Octokit.
+ * Returns a loaded Octokit. If state is passed and authentication
+ * is available, we'll token-authenticate.
  *
  * @export
  * @returns {Promise<typeof GitHubType>}
  */
-export async function getOctokit(): Promise<GitHubType> {
+export async function getOctokit(
+  appState?: AppState
+): Promise<GitHubType> {
   _Octokit = _Octokit || (await import('@octokit/rest') as any).default;
-  return _octo = _octo || new _Octokit();
+  _octo = _octo || new _Octokit();
+
+  // You can load Gists without being authenticated,
+  // but we get better rate limits when authenticated
+  if (appState && appState.gitHubToken) {
+    _octo.authenticate({
+      type: 'token',
+      token: appState.gitHubToken!
+    });
+  }
+
+  return _octo;
 }

src/utils/random.ts

@@ -0,0 +1,12 @@
+/**
+ * Dumb helper: Get a random number between two numbers
+ *
+ * @param {number} [min=0]
+ * @param {number} [max=1]
+ * @returns {number}
+ */
+export function getRandomNumber(
+  min: number = 0, max: number = 1
+): number {
+  return Math.floor(Math.random() * max) + min;
+}

src/utils/set-about-panel.ts

@@ -0,0 +1,28 @@
+import { AboutPanelOptionsOptions, app } from 'electron';
+
+/**
+ * Sets Fiddle's About panel options on Linux and macOS
+ *
+ * @returns
+ */
+export function setupAboutPanel(): void {
+  if (process.platform === 'win32') return;
+
+  const options: AboutPanelOptionsOptions = {
+    applicationName: 'Electron Fiddle',
+    applicationVersion: app.getVersion(),
+    version: process.versions.electron,
+    copyright: '© Electron Authors',
+  };
+
+  switch (process.platform) {
+    case 'linux':
+      options.website = 'https://electronjs.org/fiddle';
+    case 'darwin':
+      options.credits = 'https://github.com/electron/fiddle/graphs/contributors';
+    default:
+      // fallthrough
+  }
+
+  app.setAboutPanelOptions(options);
+}

src/utils/type-checks.ts

@@ -0,0 +1,35 @@
+import { ALL_EDITORS, EditorId, MosaicId, PanelId } from '../interfaces';
+import { EditorBackup } from './editor-backup';
+
+/**
+ * Is the given string of type `EditorId`?
+ *
+ * @export
+ * @param {(EditorId | PanelId | MosaicId)} input
+ * @returns {input is EditorId}
+ */
+export function isEditorId(input: EditorId | PanelId | MosaicId): input is EditorId {
+  return (ALL_EDITORS as any).includes(input);
+}
+
+/**
+ * Is the given string of type `isPanelId`?
+ *
+ * @export
+ * @param {(EditorId | PanelId | MosaicId)} input
+ * @returns {input is MosaicId}
+ */
+export function isPanelId(input: EditorId | PanelId | MosaicId): input is PanelId {
+  return !(ALL_EDITORS as any).includes(input);
+}
+
+/**
+ * Is the given input of type `EditorBackup`?
+ *
+ * @export
+ * @param {(EditorBackup | true)} input
+ * @returns {input is EditorBackup}
+ */
+export function isEditorBackup(input?: EditorBackup | true | null): input is EditorBackup {
+  return !!(input && input !== true);
+}

static/entitlements.plist

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+  <dict>
+    <key>com.apple.security.cs.allow-jit</key>
+    <true/>
+    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
+    <true/>
+    <key>com.apple.security.cs.debugger</key>
+    <true/>
+  </dict>
+</plist>