clean main process desktop_capturer

lib/browser/desktop-capturer.js

@@ -1,23 +1,23 @@
 'use strict'
 
-const ipcMain = require('electron').ipcMain
-const desktopCapturer = process.atomBinding('desktop_capturer').desktopCapturer
+const {ipcMain} = require('electron')
+const {desktopCapturer} = process.atomBinding('desktop_capturer')
 
-var deepEqual = function (opt1, opt2) {
-  return JSON.stringify(opt1) === JSON.stringify(opt2)
-}
+const deepEqual = (a, b) => JSON.stringify(a) === JSON.stringify(b)
 
 // A queue for holding all requests from renderer process.
-var requestsQueue = []
+let requestsQueue = []
 
-ipcMain.on('ELECTRON_BROWSER_DESKTOP_CAPTURER_GET_SOURCES', function (event, captureWindow, captureScreen, thumbnailSize, id) {
-  var request
-  request = {
-    id: id,
+const electronSources = 'ELECTRON_BROWSER_DESKTOP_CAPTURER_GET_SOURCES'
+const capturerResult = (id) => `ELECTRON_RENDERER_DESKTOP_CAPTURER_RESULT_${id}`
+
+ipcMain.on(electronSources, (event, captureWindow, captureScreen, thumbnailSize, id) => {
+  const request = {
+    id,
     options: {
-      captureWindow: captureWindow,
-      captureScreen: captureScreen,
-      thumbnailSize: thumbnailSize
+      captureWindow,
+      captureScreen,
+      thumbnailSize
     },
     webContents: event.sender
   }
@@ -28,45 +28,47 @@ ipcMain.on('ELECTRON_BROWSER_DESKTOP_CAPTURER_GET_SOURCES', function (event, cap
 
   // If the WebContents is destroyed before receiving result, just remove the
   // reference from requestsQueue to make the module not send the result to it.
-  event.sender.once('destroyed', function () {
+  event.sender.once('destroyed', () => {
     request.webContents = null
+    return
   })
 })
 
-desktopCapturer.emit = function (event, name, sources) {
+desktopCapturer.emit = (event, name, sources) => {
   // Receiving sources result from main process, now send them back to renderer.
-  var handledRequest, i, len, ref, ref1, request, result, source, unhandledRequestsQueue
-  handledRequest = requestsQueue.shift(0)
-  result = (function () {
-    var i, len, results
-    results = []
-    for (i = 0, len = sources.length; i < len; i++) {
-      source = sources[i]
+  const handledRequest = requestsQueue.shift(0)
+  const handledWebContents = handledRequest.webContents
+  const unhandledRequestsQueue = []
+
+  const result = () => {
+    const results = []
+    sources.forEach(source => {
       results.push({
         id: source.id,
         name: source.name,
         thumbnail: source.thumbnail.toDataURL()
       })
-    }
+    })
     return results
-  })()
-  if ((ref = handledRequest.webContents) != null) {
-    ref.send('ELECTRON_RENDERER_DESKTOP_CAPTURER_RESULT_' + handledRequest.id, result)
+  }
+
+  if (handledWebContents != null) {
+    handledWebContents.send(capturerResult(handledRequest.id), result())
   }
 
   // Check the queue to see whether there is other same request. If has, handle
   // it for reducing redunplicated `desktopCaptuer.startHandling` calls.
-  unhandledRequestsQueue = []
-  for (i = 0, len = requestsQueue.length; i < len; i++) {
-    request = requestsQueue[i]
+
+  requestsQueue.forEach(request => {
+    const webContents = request.webContents
     if (deepEqual(handledRequest.options, request.options)) {
-      if ((ref1 = request.webContents) != null) {
-        ref1.send('ELECTRON_RENDERER_DESKTOP_CAPTURER_RESULT_' + request.id, result)
+      if (webContents != null) {
+        webContents.send(capturerResult(request.id), result())
       }
     } else {
       unhandledRequestsQueue.push(request)
     }
-  }
+  })
   requestsQueue = unhandledRequestsQueue
 
   // If the requestsQueue is not empty, start a new request handling.