webpack.prod.js

const path = require('path');
const {
    CleanWebpackPlugin
} = require('clean-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
const buildPath = path.resolve(__dirname, 'dist');

module.exports = {

    // This option controls if and how source maps are generated.
    // https://webpack.js.org/configuration/devtool/
    devtool: 'source-map',

    // https://webpack.js.org/concepts/entry-points/#multi-page-application
    entry: {
        index: './src/index.js'
    },

    // how to write the compiled files to disk
    // https://webpack.js.org/concepts/output/
    output: {
        filename: '[name].[hash:20].js',
        path: buildPath
    },

    // https://webpack.js.org/concepts/loaders/
    module: {
        rules: [{
                test: /\.js$/,
                exclude: /node_modules/,
                loader: 'babel-loader',
                options: {
                    presets: ['@babel/preset-env']
                }
            },
            {
                test: /\.scss$/,
                use: [
                    "style-loader",
                    MiniCssExtractPlugin.loader,
                    "css-loader",
                    {
                        loader: 'sass-loader',
                        options: {
                            sourceMap: true
                        }
                    }
                ]
            },
            {
                test: /\.(png|jpg|gif|svg)$/,
                use: [{
                    loader: 'url-loader',
                    options: {
                        // On development we want to see where the file is coming from, hence we preserve the [path]
                        name: '[path][name].[ext]?hash=[hash:20]',
                        limit: 8192
                    }
                }]
            }
        ]
    },

    // https://webpack.js.org/concepts/plugins/
    plugins: [
        new CleanWebpackPlugin(),
        new HtmlWebpackPlugin({
            template: './src/index.html',
            inject: 'body',
            chunks: ['index'],
            filename: 'index.html'
        }),
        new MiniCssExtractPlugin({
            filename: "[name].[contenthash].css",
            chunkFilename: "[id].[contenthash].css"
        })
    ],

    // https://webpack.js.org/configuration/optimization/
    optimization: {
        minimizer: [
            new UglifyJsPlugin({
                cache: true,
                parallel: true,
                sourceMap: true
            }),
            new OptimizeCssAssetsPlugin({})
        ]
    }
};