Switch from uglifyjs-webpack-plugin to terser-webpack-plugin

Some history:
* `uglifyjs-webpack-plugin` < v1.0 used the minifier `uglify-js`
* however `uglify-js` does not support ES6, which resulted in a fork
  called `uglify-es` that was developed in the `uglify-js` repository,
  but under the `harmony` branch
* `uglifyjs-webpack-plugin` v1.x switched to `uglify-es` for ES6 support
* however `uglify-es` stopped being maintained:
  mishoo/UglifyJS#3156 (comment)
* which led to a fork called `terser` that has incorporated all of
  the unmerged PRs and will be where all new development occurs:
  https://github.com/fabiosantoscode/terser
* `terser-webpack-plugin` was created, which is the `terser` equivalent
  of `uglifyjs-webpack-plugin`:
  https://github.com/webpack-contrib/terser-webpack-plugin
* `uglifyjs-webpack-plugin` v2.x will be switching back to `uglify-js`,
  so any project that needs to support ES6 now needs to switch to
  `terser-webpack-plugin`.

Fixes webpack#7923.

Author: edmorley

benchmark/createBenchmark.js

@@ -15,7 +15,7 @@ webpack(
 		},
 		plugins: [
 			new webpack.NamedModulesPlugin(),
-			new webpack.IgnorePlugin(/^(fsevents|uglify-js)$/),
+			new webpack.IgnorePlugin(/^(fsevents|terser)$/),
 			new webpack.NormalModuleReplacementPlugin(
 				/^.\/loadLoader$/,
 				path.resolve(__dirname, "./createBenchmark/loadLoader")

examples/code-splitted-css-bundle/README.md

@@ -101,7 +101,7 @@ Child extract-text-webpack-plugin ../../node_modules/extract-text-webpack-plugin
          + 1 hidden module
 ```
 
-## Minimized (uglify-js, no zip)
+## Minimized (terser, no zip)
 
 ```
 Hash: edbe0e91ba86d814d855

lib/WebpackOptionsDefaulter.js

@@ -302,10 +302,10 @@ class WebpackOptionsDefaulter extends OptionsDefaulter {
 		this.set("optimization.minimizer", "make", options => [
 			{
 				apply: compiler => {
-					// Lazy load the uglifyjs plugin
-					const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
+					// Lazy load the Terser plugin
+					const TerserPlugin = require("terser-webpack-plugin");
 					const SourceMapDevToolPlugin = require("./SourceMapDevToolPlugin");
-					new UglifyJsPlugin({
+					new TerserPlugin({
 						cache: true,
 						parallel: true,
 						sourceMap:

package.json

@@ -26,7 +26,7 @@
     "node-libs-browser": "^2.0.0",
     "schema-utils": "^0.4.4",
     "tapable": "^1.1.0",
-    "uglifyjs-webpack-plugin": "^1.2.4",
+    "terser-webpack-plugin": "^1.1.0",
     "watchpack": "^1.5.0",
     "webpack-sources": "^1.3.0"
   },

test/TestCases.template.js

@@ -5,14 +5,14 @@ const path = require("path");
 const fs = require("fs");
 const vm = require("vm");
 const mkdirp = require("mkdirp");
-const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
+const TerserPlugin = require("terser-webpack-plugin");
 const checkArrayExpectation = require("./checkArrayExpectation");
 const createLazyTestEnv = require("./helpers/createLazyTestEnv");
 
 const Stats = require("../lib/Stats");
 const webpack = require("../lib/webpack");
 
-const uglifyJsForTesting = new UglifyJsPlugin({
+const terserForTesting = new TerserPlugin({
 	cache: false,
 	parallel: false,
 	sourceMap: true
@@ -31,12 +31,12 @@ const DEFAULT_OPTIMIZATIONS = {
 	concatenateModules: false,
 	namedModules: false,
 	hashedModuleIds: false,
-	minimizer: [uglifyJsForTesting]
+	minimizer: [terserForTesting]
 };
 
 const NO_EMIT_ON_ERRORS_OPTIMIZATIONS = {
 	noEmitOnErrors: false,
-	minimizer: [uglifyJsForTesting]
+	minimizer: [terserForTesting]
 };
 
 const casesPath = path.join(__dirname, "cases");

test/__snapshots__/StatsTestCases.test.js.snap

@@ -1,7 +1,7 @@
 const supportsOptionalCatchBinding = require("../../../helpers/supportsOptionalCatchBinding");
 
 module.exports = function(config) {
-	// XXX: Disable this test if UglifyJS is used because it does not support ES 2019
+	// XXX: Disable this test if Terser is used because it does not support ES 2019
 	if (config.mode === "production") {
 		return false;
 	}

test/cases/parsing/optional-catch-binding/test.filter.js

@@ -17,7 +17,7 @@ module.exports = function checkArrayExpectation(
 	}
 	let array = object[`${kind}s`].slice().sort();
 	if (kind === "warning")
-		array = array.filter(item => !/from UglifyJs/.test(item));
+		array = array.filter(item => !/from Terser/.test(item));
 	if (fs.existsSync(path.join(testDirectory, `${filename}.js`))) {
 		const expectedFilename = path.join(testDirectory, `${filename}.js`);
 		const expected = require(expectedFilename);

test/checkArrayExpectation.js

@@ -1,5 +1,5 @@
 var webpack = require("../../../../");
-var UglifyJsPlugin = require("uglifyjs-webpack-plugin");
+var TerserPlugin = require("terser-webpack-plugin");
 module.exports = {
 	node: {
 		__dirname: false,
@@ -14,7 +14,7 @@ module.exports = {
 	},
 	optimization: {
 		minimizer: [
-			new UglifyJsPlugin({
+			new TerserPlugin({
 				sourceMap: true
 			})
 		]

test/configCases/plugins/source-map-dev-tool-plugin/webpack.config.js

@@ -1,4 +1,4 @@
-const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
+const TerserPlugin = require("terser-webpack-plugin");
 module.exports = {
 	node: {
 		__dirname: false,
@@ -17,21 +17,21 @@ module.exports = {
 	optimization: {
 		minimize: true,
 		minimizer: [
-			new UglifyJsPlugin({
+			new TerserPlugin({
 				cache: false,
 				parallel: false,
 				exclude: ["vendors.js", "extract.js"]
 			}),
-			new UglifyJsPlugin({
+			new TerserPlugin({
 				cache: false,
 				parallel: false,
 				extractComments: true,
 				include: ["extract.js"]
 			}),
-			new UglifyJsPlugin({
+			new TerserPlugin({
 				cache: false,
 				parallel: false,
-				uglifyOptions: {
+				terserOptions: {
 					compress: {
 						passes: 2
 					}