Babel: use for...of transform for client scripts (#2783)

package.json

@@ -57,6 +57,7 @@
     "async-exit-hook": "^1.1.2",
     "babel-core": "^6.22.1",
     "babel-plugin-transform-class-properties": "^6.24.1",
+    "babel-plugin-transform-for-of-as-array": "^1.1.1",
     "babel-plugin-transform-runtime": "^6.22.0",
     "babel-preset-env": "^1.1.8",
     "babel-preset-flow": "^6.23.0",

src/client/.babelrc

@@ -1,9 +1,15 @@
 {
   "compact": false,
   "presets": [
-    ["env", { "loose": true }]
+    ["env", {
+      "loose": true,
+      "exclude": [
+        "transform-es2015-typeof-symbol"
+      ]
+    }]
   ],
   "plugins": [
-    "add-module-exports"
+    "add-module-exports",
+    "transform-for-of-as-array"
   ]
 }

src/compiler/compile-client-function.js

@@ -1,6 +1,6 @@
 import hammerhead from 'testcafe-hammerhead';
 import asyncToGenerator from 'babel-runtime/helpers/asyncToGenerator';
-import { noop, escapeRegExp as escapeRe } from 'lodash';
+import { noop } from 'lodash';
 import loadBabelLibs from './load-babel-libs';
 import { ClientFunctionAPIError } from '../errors/runtime';
 import MESSAGE from '../errors/runtime/message';
@@ -29,27 +29,15 @@ var babelArtifactPolyfills = {
         re:                 /_stringify(\d+)\.default/,
         getCode:            match => `var _stringify${match[1]} = { default: JSON.stringify };`,
         removeMatchingCode: false
-    },
-
-    'typeof': {
-        re: new RegExp(escapeRe(
-            'var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? ' +
-            'function (obj) {return typeof obj;} : ' +
-            'function (obj) {return obj && typeof Symbol === "function" && obj.constructor === Symbol ' +
-            '&& obj !== Symbol.prototype ? "symbol" : typeof obj;};'
-        ), 'g'),
-
-        getCode:            () => 'var _typeof = function(obj) { return typeof obj; };',
-        removeMatchingCode: true
     }
 };
 
 
 function getBabelOptions () {
-    var { presetFallback } = loadBabelLibs();
+    var { presetFallback, transformForOfAsArray } = loadBabelLibs();
 
     return {
-        presets:       [presetFallback],
+        presets:       [{ plugins: [transformForOfAsArray] }, presetFallback],
         sourceMaps:    false,
         retainLines:   true,
         ast:           false,

src/compiler/load-babel-libs.js

@@ -6,6 +6,13 @@ function getOptsForPresetEnv () {
     };
 }
 
+function getOptsForPresetFallback () {
+    return {
+        loose:   true,
+        exclude: ['transform-es2015-typeof-symbol']
+    };
+}
+
 // NOTE: lazy load heavy dependencies
 export default function loadBabelLibs () {
     return {
@@ -14,7 +21,8 @@ export default function loadBabelLibs () {
         presetFlow:               require('babel-preset-flow'),
         transformClassProperties: require('babel-plugin-transform-class-properties'),
         transformRuntime:         require('babel-plugin-transform-runtime'),
-        presetFallback:           require('babel-preset-env').default(null, { loose: true }),
+        transformForOfAsArray:    require('babel-plugin-transform-for-of-as-array').default,
+        presetFallback:           require('babel-preset-env').default(null, getOptsForPresetFallback()),
         presetEnv:                require('babel-preset-env').default(null, getOptsForPresetEnv())
     };
 }

test/server/compiler-test.js

@@ -455,10 +455,6 @@ describe('Compiler', function () {
             return testClientFnCompilation('json-stringify');
         });
 
-        it('Should polyfill Babel `typeof` artifacts', function () {
-            return testClientFnCompilation('typeof');
-        });
-
         describe('Regression', function () {
             it('Should compile ES6 object method (GH-1279)', function () {
                 return testClientFnCompilation('gh1279');