Convert var's to let's

This patch:
- converts all var's to let's throughout the codebase
- enforces the let's over var's via the eslint rule

.eslintrc.js

@@ -49,6 +49,7 @@ module.exports = {
         "arrow-parens": [2, "as-needed"],
 
         // anti-patterns
+        "no-var": 2,
         "no-with": 2,
         "no-multi-str": 2,
         "no-caller": 2,
@@ -99,13 +100,11 @@ module.exports = {
         "no-mixed-spaces-and-tabs": 2,
         "no-trailing-spaces": 2,
         "linebreak-style": [ 2, "unix" ],
+        "indent": [2, 2, { "SwitchCase": 1, "CallExpression": {"arguments": 2}, "MemberExpression": 2 }],
 
         /**
          * Disabled, aspirational rules
          */
-
-        "indent": [2, 2, { "SwitchCase": 1, "CallExpression": {"arguments": 2}, "MemberExpression": 2 }],
-
         // brace-style is disabled, as eslint cannot enforce 1tbs as default, but allman for functions
         "brace-style": [0, "allman", { "allowSingleLine": true }],
 

install.js

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-var Downloader = require('./utils/ChromiumDownloader');
-var revision = require('./package').puppeteer.chromium_revision;
-var ProgressBar = require('progress');
+let Downloader = require('./utils/ChromiumDownloader');
+let revision = require('./package').puppeteer.chromium_revision;
+let ProgressBar = require('progress');
 
 // Do nothing if the revision is already downloaded.
 if (Downloader.revisionInfo(Downloader.currentPlatform(), revision))
@@ -27,7 +27,7 @@ Downloader.downloadRevision(Downloader.currentPlatform(), revision, onProgress)
       console.error('Download failed: ' + error.message);
     });
 
-var progressBar = null;
+let progressBar = null;
 function onProgress(bytesTotal, delta) {
   if (!progressBar) {
     progressBar = new ProgressBar(`Downloading Chromium - ${toMegabytes(bytesTotal)} [:bar] :percent :etas `, {
@@ -41,7 +41,7 @@ function onProgress(bytesTotal, delta) {
 }
 
 function toMegabytes(bytes) {
-  var mb = bytes / 1024 / 1024;
+  let mb = bytes / 1024 / 1024;
   return (Math.round(mb * 10) / 10) + ' Mb';
 }
 

lib/Browser.js

@@ -14,18 +14,18 @@
  * limitations under the License.
  */
 
-var http = require('http');
-var path = require('path');
-var removeRecursive = require('rimraf').sync;
-var Page = require('./Page');
-var childProcess = require('child_process');
-var Downloader = require('../utils/ChromiumDownloader');
-var Connection = require('./Connection');
+let http = require('http');
+let path = require('path');
+let removeRecursive = require('rimraf').sync;
+let Page = require('./Page');
+let childProcess = require('child_process');
+let Downloader = require('../utils/ChromiumDownloader');
+let Connection = require('./Connection');
 
-var CHROME_PROFILE_PATH = path.resolve(__dirname, '..', '.dev_profile');
-var browserId = 0;
+let CHROME_PROFILE_PATH = path.resolve(__dirname, '..', '.dev_profile');
+let browserId = 0;
 
-var DEFAULT_ARGS = [
+let DEFAULT_ARGS = [
   '--disable-background-timer-throttling',
   '--no-first-run',
 ];
@@ -54,8 +54,8 @@ class Browser {
     if (typeof options.executablePath === 'string') {
       this._chromeExecutable = options.executablePath;
     } else {
-      var chromiumRevision = require('../package.json').puppeteer.chromium_revision;
-      var revisionInfo = Downloader.revisionInfo(Downloader.currentPlatform(), chromiumRevision);
+      let chromiumRevision = require('../package.json').puppeteer.chromium_revision;
+      let revisionInfo = Downloader.revisionInfo(Downloader.currentPlatform(), chromiumRevision);
       console.assert(revisionInfo, 'Chromium revision is not downloaded. Run npm install');
       this._chromeExecutable = revisionInfo.executablePath;
     }
@@ -72,8 +72,8 @@ class Browser {
     await this._ensureChromeIsRunning();
     if (!this._chromeProcess || this._terminated)
       throw new Error('ERROR: this chrome instance is not alive any more!');
-    var client = await Connection.create(this._remoteDebuggingPort);
-    var page = await Page.create(client);
+    let client = await Connection.create(this._remoteDebuggingPort);
+    let page = await Page.create(client);
     return page;
   }
 
@@ -91,15 +91,15 @@ class Browser {
      */
   async version() {
     await this._ensureChromeIsRunning();
-    var version = await Connection.version(this._remoteDebuggingPort);
+    let version = await Connection.version(this._remoteDebuggingPort);
     return version.Browser;
   }
 
   async _ensureChromeIsRunning() {
     if (this._chromeProcess)
       return;
     this._chromeProcess = childProcess.spawn(this._chromeExecutable, this._chromeArguments, {});
-    var stderr = '';
+    let stderr = '';
     this._chromeProcess.stderr.on('data', data => stderr += data.toString('utf8'));
     // Cleanup as processes exit.
     process.on('exit', () => this._chromeProcess.kill());
@@ -123,20 +123,20 @@ class Browser {
 module.exports = Browser;
 
 function waitForChromeResponsive(remoteDebuggingPort, shouldWaitCallback) {
-  var fulfill;
-  var promise = new Promise(x => fulfill = x);
-  var options = {
+  let fulfill;
+  let promise = new Promise(x => fulfill = x);
+  let options = {
     method: 'GET',
     host: 'localhost',
     port: remoteDebuggingPort,
     path: '/json/list'
   };
-  var probeTimeout = 100;
+  let probeTimeout = 100;
   sendRequest();
   return promise;
 
   function sendRequest() {
-    var req = http.request(options, res => {
+    let req = http.request(options, res => {
       fulfill();
     });
     req.on('error', e => {

lib/Connection.js

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-var EventEmitter = require('events');
-var WebSocket = require('ws');
-var http = require('http');
+let EventEmitter = require('events');
+let WebSocket = require('ws');
+let http = require('http');
 const COMMAND_TIMEOUT = 10000;
 
 class Connection extends EventEmitter {
@@ -44,8 +44,8 @@ class Connection extends EventEmitter {
    * @return {!Promise<?Object>}
    */
   send(method, params = {}) {
-    var id = ++this._lastId;
-    var message = JSON.stringify({id, method, params});
+    let id = ++this._lastId;
+    let message = JSON.stringify({id, method, params});
     this._ws.send(message);
     return new Promise((resolve, reject) => {
       this._callbacks.set(id, {resolve, reject, method});
@@ -56,9 +56,9 @@ class Connection extends EventEmitter {
    * @param {string} message
    */
   _onMessage(message) {
-    var object = JSON.parse(message);
+    let object = JSON.parse(message);
     if (object.id && this._callbacks.has(object.id)) {
-      var callback = this._callbacks.get(object.id);
+      let callback = this._callbacks.get(object.id);
       this._callbacks.delete(object.id);
       if (object.error)
         callback.reject(new Error(`Protocol error (${callback.method}): ${object.error.message}`));
@@ -87,11 +87,11 @@ class Connection extends EventEmitter {
    * @return {!Promise<!Connection>}
    */
   static async create(port) {
-    var newTab = await runJsonCommand(port, 'new');
-    var url = newTab.webSocketDebuggerUrl;
+    let newTab = await runJsonCommand(port, 'new');
+    let url = newTab.webSocketDebuggerUrl;
 
     return new Promise((resolve, reject) => {
-      var ws = new WebSocket(url, { perMessageDeflate: false });
+      let ws = new WebSocket(url, { perMessageDeflate: false });
       ws.on('open', () => resolve(new Connection(port, newTab.id, ws)));
       ws.on('error', reject);
     });
@@ -112,17 +112,17 @@ class Connection extends EventEmitter {
  * @return {!Promise<!Object>}
  */
 function runJsonCommand(port, command) {
-  var request = http.get({
+  let request = http.get({
     hostname: 'localhost',
     port: port,
     path: '/json/' + command
   }, onResponse);
   request.setTimeout(COMMAND_TIMEOUT, onTimeout);
-  var resolve, reject;
+  let resolve, reject;
   return new Promise((res, rej) => { resolve = res; reject = rej; });
 
   function onResponse(response) {
-    var data = '';
+    let data = '';
     response.on('data', chunk => data += chunk);
     response.on('end', () => {
       if (response.statusCode !== 200) {

lib/FrameManager.js

@@ -14,15 +14,15 @@
  * limitations under the License.
  */
 
-var EventEmitter = require('events');
+let EventEmitter = require('events');
 
 class FrameManager extends EventEmitter {
   /**
    * @param {!Connection} client
    * @return {!FrameManager}
    */
   static async create(client) {
-    var mainFramePayload = await client.send('Page.getResourceTree');
+    let mainFramePayload = await client.send('Page.getResourceTree');
     return new FrameManager(client, mainFramePayload.frameTree);
   }
 
@@ -70,8 +70,8 @@ class FrameManager extends EventEmitter {
       this._navigateFrame(this._mainFrame, frameId, null);
       return;
     }
-    var parentFrame = this._frames.get(parentFrameId);
-    var frame = new Frame(parentFrame, frameId, null);
+    let parentFrame = this._frames.get(parentFrameId);
+    let frame = new Frame(parentFrame, frameId, null);
     this._frames.set(frame._id, frame);
     this.emit(FrameManager.Events.FrameAttached, frame);
   }
@@ -80,7 +80,7 @@ class FrameManager extends EventEmitter {
    * @param {!Object} framePayload
    */
   _frameNavigated(framePayload) {
-    var frame = this._frames.get(framePayload.id);
+    let frame = this._frames.get(framePayload.id);
     if (!frame) {
       // Simulate missed "frameAttached" for a main frame navigation to the new backend process.
       console.assert(!framePayload.parentId, 'Main frame shouldn\'t have parent frame id.');
@@ -93,7 +93,7 @@ class FrameManager extends EventEmitter {
    * @param {string} frameId
    */
   _frameDetached(frameId) {
-    var frame = this._frames.get(frameId);
+    let frame = this._frames.get(frameId);
     if (frame)
       this._removeFramesRecursively(frame);
   }
@@ -105,7 +105,7 @@ class FrameManager extends EventEmitter {
    */
   _navigateFrame(frame, newFrameId, newFramePayload) {
     // Detach all child frames first.
-    for (var child of frame.childFrames())
+    for (let child of frame.childFrames())
       this._removeFramesRecursively(child);
     this._frames.delete(frame._id, frame);
     frame._id = newFrameId;
@@ -120,11 +120,11 @@ class FrameManager extends EventEmitter {
    * @return {!Frame}
    */
   _addFramesRecursively(parentFrame, frameTreePayload) {
-    var framePayload = frameTreePayload.frame;
-    var frame = new Frame(parentFrame, framePayload.id, framePayload);
+    let framePayload = frameTreePayload.frame;
+    let frame = new Frame(parentFrame, framePayload.id, framePayload);
     this._frames.set(frame._id, frame);
 
-    for (var i = 0; frameTreePayload.childFrames && i < frameTreePayload.childFrames.length; ++i)
+    for (let i = 0; frameTreePayload.childFrames && i < frameTreePayload.childFrames.length; ++i)
       this._addFramesRecursively(frame, frameTreePayload.childFrames[i]);
     return frame;
   }
@@ -133,7 +133,7 @@ class FrameManager extends EventEmitter {
    * @param {!Frame} frame
    */
   _removeFramesRecursively(frame) {
-    for (var child of frame.childFrames())
+    for (let child of frame.childFrames())
       this._removeFramesRecursively(child);
     frame._detach();
     this._frames.delete(frame._id);

lib/Navigator.js

@@ -39,7 +39,7 @@ class Navigator {
     this._minimumTimer = setTimeout(this._completeNavigation.bind(this, false), this._minTime);
     let onload = new Promise(fulfill => this._client.once('Page.loadEventFired', fulfill));
     let networkIdle = new Promise(fulfill => this._navigationLoadCallback = fulfill);
-    var interstitialPromise = new Promise(fulfill => this._client.once('Security.certificateError', fulfill)).then(() => false);
+    let interstitialPromise = new Promise(fulfill => this._client.once('Security.certificateError', fulfill)).then(() => false);
 
     this._inflightRequests = 0;
     // Await for the command to throw exception in case of illegal arguments.