build: use typescript for internal Electron JS code (electron#16441)

.eslintrc.json

@@ -1,12 +1,21 @@
 {
   "extends": "standard",
+  "parser": "typescript-eslint-parser",
+  "plugins": ["typescript"],
   "env": {
     "browser": true
   },
   "rules": {
     "no-var": "error",
+    "no-unused-vars": 0,
+    "no-global-assign": 0,
+    "typescript/no-unused-vars": "error",
     "prefer-const": ["error", {
       "destructuring": "all"
     }]
+  },
+  "parserOptions": {
+    "ecmaVersion": 6,
+    "sourceType": "module"
   }
 }

.gitignore

@@ -59,3 +59,6 @@ spec/.hash
 
 # Generated native addon files
 /spec/fixtures/native-addon/echo/build/
+
+# If someone runs tsc this is where stuff will end up
+ts-gen

BUILD.gn

@@ -11,8 +11,10 @@ import("//tools/v8_context_snapshot/v8_context_snapshot.gni")
 import("//v8/snapshot_toolchain.gni")
 import("build/asar.gni")
 import("build/npm.gni")
+import("build/tsc.gni")
 import("buildflags/buildflags.gni")
 import("electron_paks.gni")
+import("filenames.auto.gni")
 import("filenames.gni")
 
 if (is_mac) {
@@ -53,6 +55,21 @@ config("branding") {
   ]
 }
 
+# We geneate the definitions twice here, once in //electron/electron.d.ts
+# and once in $target_gen_dir
+# The one in $target_gen_dir is used for the actual TSC build later one
+# and the one in //electron/electron.d.ts is used by your IDE (vscode)
+# for typescript prompting
+npm_action("build_electron_definitions") {
+  script = "gn-typescript-definitions"
+  args = [ rebase_path("$target_gen_dir/tsc/typings/electron.d.ts") ]
+  inputs = auto_filenames.api_docs + [ "package-lock.json" ]
+
+  outputs = [
+    "$target_gen_dir/tsc/typings/electron.d.ts",
+  ]
+}
+
 npm_action("atom_browserify_sandbox") {
   script = "browserify"
 
@@ -140,9 +157,12 @@ action("atom_js2c") {
 target_gen_electron_js = "$target_gen_dir/js/electron"
 target_gen_default_app_js = "$target_gen_dir/js/default_app"
 
-# TODO(MarshallOfSound)
-# This copy will be replaced by a call to tsc in the future
-copy("lib_js") {
+typescript_build("lib_js") {
+  deps = [
+    ":build_electron_definitions",
+  ]
+  type_root = rebase_path("$target_gen_dir/tsc/electron/typings")
+
   sources = filenames.js_sources
   if (enable_desktop_capturer) {
     sources += [
@@ -162,9 +182,9 @@ copy("lib_js") {
     ]
   }
 
-  outputs = [
-    "$target_gen_electron_js/{{source}}",
-  ]
+  output_gen_dir = target_gen_electron_js
+  output_dir_name = "lib"
+  tsconfig = "tsconfig.electron.json"
 }
 
 asar("electron_asar") {
@@ -179,8 +199,21 @@ asar("electron_asar") {
   ]
 }
 
-copy("default_app_js") {
-  sources = filenames.default_app_sources
+typescript_build("default_app_js") {
+  deps = [
+    ":build_electron_definitions",
+  ]
+  type_root = rebase_path("$target_gen_dir/tsc/electron/typings")
+
+  sources = filenames.default_app_ts_sources
+
+  output_gen_dir = target_gen_default_app_js
+  output_dir_name = "default_app"
+  tsconfig = "tsconfig.default_app.json"
+}
+
+copy("default_app_static") {
+  sources = filenames.default_app_static_sources
   outputs = [
     "$target_gen_default_app_js/{{source}}",
   ]
@@ -197,10 +230,12 @@ asar("default_app_asar") {
   deps = [
     ":default_app_js",
     ":default_app_octicon_deps",
+    ":default_app_static",
   ]
 
   root = "$target_gen_default_app_js/electron/default_app"
   sources = get_target_outputs(":default_app_js") +
+            get_target_outputs(":default_app_static") +
             get_target_outputs(":default_app_octicon_deps")
   outputs = [
     "$root_out_dir/resources/default_app.asar",

build/tsc.gni

@@ -0,0 +1,50 @@
+import("npm.gni")
+
+template("typescript_build") {
+  assert(defined(invoker.tsconfig), "Need tsconfig name to run")
+  assert(defined(invoker.sources), "Need tsc sources to run")
+  assert(defined(invoker.output_dir_name),
+         "Need output_dir_name to run, should be 'lib' or other top level dir")
+  assert(defined(invoker.output_gen_dir),
+         "Need output_gen_dir to run, should be relative to the root gen dir")
+
+  npm_action(target_name) {
+    forward_variables_from(invoker,
+                           [
+                             "deps",
+                             "public_deps",
+                             "outputs",
+                           ])
+    script = "tsc"
+
+    sources = invoker.sources
+    inputs = [
+      invoker.tsconfig,
+      "//electron/tsconfig.json",
+      "//electron/package-lock.json",
+    ]
+
+    type_roots = "node_modules/@types,typings"
+    if (defined(invoker.type_root)) {
+      type_roots += "," + invoker.type_root
+    }
+
+    base_out_path = invoker.output_gen_dir + "/electron/"
+    args = [
+      "-p",
+      rebase_path(invoker.tsconfig),
+      "--outDir",
+      rebase_path("$base_out_path" + invoker.output_dir_name),
+      "--typeRoots",
+      type_roots,
+    ]
+
+    outputs = []
+
+    foreach(invoker_source, invoker.sources) {
+      # The output of TSC is all inputs but with JS instead of TS as the extension
+      outputs += [ "$base_out_path" + get_path_info(invoker_source, "dir") +
+                   "/" + get_path_info(invoker_source, "name") + ".js" ]
+    }
+  }
+}

default_app/default_app.js → default_app/default_app.ts

@@ -1,19 +1,17 @@
-'use strict'
+import { app, BrowserWindow, BrowserWindowConstructorOptions } from 'electron'
+import * as path from 'path'
 
-const { app, BrowserWindow } = require('electron')
-const path = require('path')
-
-let mainWindow = null
+let mainWindow: BrowserWindow | null = null
 
 // Quit when all windows are closed.
 app.on('window-all-closed', () => {
   app.quit()
 })
 
-exports.load = async (appUrl) => {
+export const load = async (appUrl: string) => {
   await app.whenReady()
 
-  const options = {
+  const options: BrowserWindowConstructorOptions = {
     width: 900,
     height: 600,
     autoHideMenuBar: true,
@@ -33,7 +31,7 @@ exports.load = async (appUrl) => {
 
   mainWindow = new BrowserWindow(options)
 
-  mainWindow.on('ready-to-show', () => mainWindow.show())
+  mainWindow.on('ready-to-show', () => mainWindow!.show())
 
   mainWindow.loadURL(appUrl)
   mainWindow.focus()

default_app/main.js → default_app/main.ts

@@ -1,20 +1,31 @@
-'use strict'
-
-const { app, dialog } = require('electron')
+import { app, dialog } from 'electron'
+
+import * as fs from 'fs'
+import * as path from 'path'
+import * as url from 'url'
+
+type DefaultAppOptions = {
+  file: null | string;
+  noHelp: boolean;
+  version: boolean;
+  webdriver: boolean;
+  interactive: boolean;
+  abi: boolean;
+  modules: string[];
+}
 
-const fs = require('fs')
 const Module = require('module')
-const path = require('path')
-const url = require('url')
 
 // Parse command line options.
 const argv = process.argv.slice(1)
 
-const option = {
+const option: DefaultAppOptions = {
   file: null,
   noHelp: Boolean(process.env.ELECTRON_NO_HELP),
-  version: null,
-  webdriver: null,
+  version: false,
+  webdriver: false,
+  interactive: false,
+  abi: false,
   modules: []
 }
 
@@ -62,7 +73,7 @@ if (option.modules.length > 0) {
   Module._preloadModules(option.modules)
 }
 
-function loadApplicationPackage (packagePath) {
+function loadApplicationPackage (packagePath: string) {
   // Add a flag indicating app is started from default app.
   Object.defineProperty(process, 'defaultApp', {
     configurable: false,
@@ -112,14 +123,15 @@ function loadApplicationPackage (packagePath) {
   }
 }
 
-function showErrorMessage (message) {
+function showErrorMessage (message: string) {
   app.focus()
   dialog.showErrorBox('Error launching app', message)
   process.exit(1)
 }
 
-function loadApplicationByUrl (appUrl) {
-  require('./default_app').load(appUrl)
+async function loadApplicationByUrl (appUrl: string) {
+  const { load } = await import('./default_app')
+  load(appUrl)
 }
 
 function startRepl () {

default_app/renderer.js → default_app/renderer.ts

@@ -1,9 +1,7 @@
-'use strict'
-
-const { remote, shell } = require('electron')
-const fs = require('fs')
-const path = require('path')
-const URL = require('url')
+import { remote, shell } from 'electron'
+import * as fs from 'fs'
+import * as path from 'path'
+import * as URL from 'url'
 
 function initialize () {
   // Find the shortest path to the electron binary
@@ -13,13 +11,13 @@ function initialize () {
     ? absoluteElectronPath
     : relativeElectronPath
 
-  for (const link of document.querySelectorAll('a[href]')) {
+  for (const link of document.querySelectorAll<HTMLLinkElement>('a[href]')) {
     // safely add `?utm_source=default_app
-    const parsedUrl = URL.parse(link.getAttribute('href'), true)
+    const parsedUrl = URL.parse(link.getAttribute('href')!, true)
     parsedUrl.query = { ...parsedUrl.query, utm_source: 'default_app' }
     const url = URL.format(parsedUrl)
 
-    const openLinkExternally = (e) => {
+    const openLinkExternally = (e: Event) => {
       e.preventDefault()
       shell.openExternalSync(url)
     }
@@ -28,13 +26,13 @@ function initialize () {
     link.addEventListener('auxclick', openLinkExternally)
   }
 
-  document.querySelector('.electron-version').innerText = `Electron v${process.versions.electron}`
-  document.querySelector('.chrome-version').innerText = `Chromium v${process.versions.chrome}`
-  document.querySelector('.node-version').innerText = `Node v${process.versions.node}`
-  document.querySelector('.v8-version').innerText = `v8 v${process.versions.v8}`
-  document.querySelector('.command-example').innerText = `${electronPath} path-to-app`
+  document.querySelector<HTMLAnchorElement>('.electron-version')!.innerText = `Electron v${process.versions.electron}`
+  document.querySelector<HTMLAnchorElement>('.chrome-version')!.innerText = `Chromium v${process.versions.chrome}`
+  document.querySelector<HTMLAnchorElement>('.node-version')!.innerText = `Node v${process.versions.node}`
+  document.querySelector<HTMLAnchorElement>('.v8-version')!.innerText = `v8 v${process.versions.v8}`
+  document.querySelector<HTMLAnchorElement>('.command-example')!.innerText = `${electronPath} path-to-app`
 
-  function getOcticonSvg (name) {
+  function getOcticonSvg (name: string) {
     const octiconPath = path.resolve(__dirname, 'octicon', `${name}.svg`)
     if (fs.existsSync(octiconPath)) {
       const content = fs.readFileSync(octiconPath, 'utf8')
@@ -45,21 +43,23 @@ function initialize () {
     return null
   }
 
-  function loadSVG (element) {
+  function loadSVG (element: HTMLSpanElement) {
     for (const cssClass of element.classList) {
       if (cssClass.startsWith('octicon-')) {
         const icon = getOcticonSvg(cssClass.substr(8))
         if (icon) {
-          icon.classList = element.classList
-          element.parentNode.insertBefore(icon, element)
+          for (const elemClass of element.classList) {
+            icon.classList.add(elemClass)
+          }
+          element.before(icon)
           element.remove()
           break
         }
       }
     }
   }
 
-  for (const element of document.querySelectorAll('.octicon')) {
+  for (const element of document.querySelectorAll<HTMLSpanElement>('.octicon')) {
     loadSVG(element)
   }
 }