Backport PR #6131: Switch webpack to production mode

Author: Zsailer

package.json

@@ -11,12 +11,15 @@
   "scripts": {
     "bower": "bower install",
     "build": "python setup.py js css",
-    "build:webpack": "webpack --mode development",
+    "build:webpack": "webpack --mode production",
     "build:watch": "npm run watch",
     "watch": "onchange 'notebook/static/**/!(*.min).js' 'notebook/static/**/*.less' 'bower.json' -- npm run build"
   },
   "devDependencies": {
+    "@babel/preset-env": "^7.15.0",
     "@jupyterlab/apputils": "^3.1.3",
+    "babel-loader": "^8.2.2",
+    "babel-polyfill": "^6.26.0",
     "bower": "^1.8.8",
     "less": "~2",
     "onchange": "^6.0.0",

webpack.config.js

@@ -1,10 +1,27 @@
 const path = require('path');
 
 module.exports = {
-  entry: '@jupyterlab/apputils/lib/sanitizer',
+  entry: ['babel-polyfill', '@jupyterlab/apputils/lib/sanitizer'],
   output: {
     filename: 'index.js',
     path: path.resolve(__dirname, 'notebook/static/components/sanitizer'),
-    libraryTarget: "amd"
+    libraryTarget: "amd",
+  },
+  devtool: false,
+  optimization: {
+    minimize: false
+  },
+  module: {
+    rules: [
+      {
+        test: /\.m?jsx?$/,
+        use: {
+          loader: 'babel-loader',
+          options: {
+            presets: ['@babel/preset-env'],
+          }
+        }
+      }
+    ]
   }
 }