Minification for ES6 code in webpack using babel

Question

I have tried options such as Uglifyjs,babelli (babel-minify ).nothing seems to be working.Uglify throws some error like this:

Name expected [au680.bundle.js:147541,22]

Answer 1

Update

If you aren't worried about supporting older browsers, webpack v4+ will minify your code by default in production mode:

webpack --mode=production

Previous answer

From https://github.com/webpack/webpack/issues/2545:

The problem is that UglifyJS doesn't support ES6 yet so it's not possible to avoid that transformation yet. You can follow the progress at mishoo/UglifyJS2#448 .

There are many solutions; here are a couple:

Transpile your ES6 code first, then minify it
For maximum compatibility, transpile using Babel and then minify with Babel Minify (formerly Babili):

1. Install babel-loader and babel-minify-webpack-plugin

   npm install babel-loader babel-minify-webpack-plugin --save-dev
   

   Or:

   yarn add babel-loader babel-minify-webpack-plugin --dev
   

2. Add this to webpack.config.js:

   const MinifyPlugin = require('babel-minify-webpack-plugin');
   
   module.exports = {
     // ...
     module: {
       rules: [
         {
           test: /\.js$/,
           use: {
             loader: 'babel-loader',
             options: {
               presets: ['env']
             }
           }
         }
       ]
     },
     plugins: [
       new MinifyPlugin()
     ]
   };
   

   Or if you prefer you can use UglifyJS instead of Babel Minify:

   const MinifyPlugin = require('uglifyjs-webpack-plugin');
   

Minify your ES6 code without transpiling
For compatibility only with browsers that support the ES6 features you're using, minify using Babel Minify without transpiling:

1. Install babel-minify-webpack-plugin

   npm install babel-minify-webpack-plugin --save-dev
   

   Or:

   yarn add babel-minify-webpack-plugin --dev
   

2. Add this to webpack.config.js:

   const MinifyPlugin = require('babel-minify-webpack-plugin');
   
   module.exports = {
     // ...
     plugins: [
       new MinifyPlugin()
     ]
   };
   

The default settings for Babel Minify worked fine for me but you can see here for more options you can customize: https://github.com/webpack-contrib/babel-minify-webpack-plugin