webpack: Transpile JS code with Babel.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

.babelrc

@@ -0,0 +1,16 @@
+{
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "corejs": 3,
+        "useBuiltIns": "usage"
+      }
+    ],
+    "@babel/typescript"
+  ],
+  "plugins": [
+    "@babel/proposal-class-properties"
+  ],
+  "sourceType": "unambiguous"
+}

.browserslistrc

@@ -0,0 +1,6 @@
+> 0.2%
+> 0.2% in US
+last 2 versions
+Firefox ESR
+not dead
+Chrome 26  # similar to PhantomJS

package.json

@@ -5,11 +5,16 @@
   "description": "",
   "main": "",
   "dependencies": {
+    "@babel/core": "^7.5.5",
+    "@babel/plugin-proposal-class-properties": "^7.5.5",
+    "@babel/preset-env": "^7.5.5",
+    "@babel/preset-typescript": "^7.3.3",
     "@types/node": "12.0.7",
     "@types/underscore": "1.8.18",
     "@types/webpack": "4.4.32",
     "@types/webpack-dev-server": "3.1.6",
     "autosize": "4.0.2",
+    "babel-loader": "^8.0.6",
     "blueimp-md5": "2.10.0",
     "cache-loader": "4.0.0",
     "clipboard": "2.0.4",
@@ -47,7 +52,6 @@
     "spectrum-colorpicker": "^1.8.0",
     "style-loader": "0.23.1",
     "to-markdown": "3.1.0",
-    "ts-loader": "6.0.2",
     "ts-node": "7.0.1",
     "typescript": "3.5.1",
     "underscore": "1.9.1",

static/js/bundles/app.js

@@ -13,7 +13,6 @@ import "xdate/src/xdate.js";
 import "jquery-validation/dist/jquery.validate.js";
 import "blueimp-md5/js/md5.js";
 import "clipboard/dist/clipboard.js";
-import "core-js/features/string/code-point-at";
 import "winchan/winchan.js";
 import "handlebars/dist/cjs/handlebars.runtime.js";
 import "to-markdown/dist/to-markdown.js";

static/js/bundles/common.js

@@ -1,7 +1,4 @@
 import "core-js/features/promise";
-import "core-js/features/string/ends-with";
-import "core-js/features/string/starts-with";
-import "core-js/features/string/code-point-at";
 import "jquery/dist/jquery.js";
 import "underscore/underscore.js";
 import "../csrf.js";

tools/webpack.config.ts

@@ -33,13 +33,11 @@ export default (env?: string): webpack.Configuration[] => {
                         },
                     ],
                 },
-                // Run the typescript compilier on .ts files before webpack
+                // Transpile .js and .ts files with Babel
                 {
-                    test: /\.tsx?$/,
-                    loader: 'ts-loader',
-                    options: {
-                        configFile: require.resolve('../static/js/tsconfig.json'),
-                    },
+                    test: /\.(js|ts)$/,
+                    include: resolve(__dirname, '../static/js'),
+                    loader: 'babel-loader',
                 },
                 // Uses script-loader on minified files so we don't change global variables in them.
                 // Also has the effect of making processing these files fast
@@ -156,7 +154,7 @@ export default (env?: string): webpack.Configuration[] => {
         { path: "sortablejs/Sortable.js"},
         { path: "winchan/winchan.js", name: 'WinChan'},
     ];
-    config.module.rules.push(...getExposeLoaders(exposeOptions));
+    config.module.rules.unshift(...getExposeLoaders(exposeOptions));
 
     if (production) {
         config.plugins = [

version.py

@@ -26,4 +26,4 @@ LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2019/03/01/zulip-2-0-relea
 #   historical commits sharing the same major version, in which case a
 #   minor version bump suffices.
 
-PROVISION_VERSION = '42.1'
+PROVISION_VERSION = '43.0'