webpack.prod.js

const path = require('path');

const CleanWebpackPlugin = require('clean-webpack-plugin'); //installed via npm
const HtmlWebpackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');

const buildPath = path.resolve(__dirname, 'public');

module.exports = {
    devtool: 'source-map',
    entry: ['./src/index.js', './src/styles/main.scss'],
    output: {
        filename: '[name].[hash:20].js',
        path: buildPath
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                loader: 'babel-loader',

                options: {
                    presets: ["es2015", "react", "stage-0"]
                }
            },
            {
                test: /\.(scss|css)$/,
                use: [
                    {
                        // creates style nodes from JS strings
                        loader: "style-loader",
                        options: {
                            sourceMap: true
                        }
                    },
                    {
                        // translates CSS into CommonJS
                        loader: "css-loader",
                        options: {
                            sourceMap: true
                        }
                    },
                    {
                        // compiles Sass to CSS
                        loader: "sass-loader",
                        options: {
                            outputStyle: 'expanded',
                            sourceMap: true,
                            sourceMapContents: true
                        }
                    }
                    // Please note we are not running postcss here
                ]
            },
            {
                // Load all images as base64 encoding if they are smaller than 8192 bytes
                test: /\.(png|jpg|gif)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            name: '[name].[hash:20].[ext]',
                            limit: 8192
                        }
                    }
                ]
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './index.html',
            // Inject the js bundle at the end of the body of the given template
            inject: 'body',
            title: 'Carousel Widget'
        }),
        new CleanWebpackPlugin(buildPath),
        new ExtractTextPlugin('styles.[md5:contenthash:hex:20].css', {
            allChunks: true
        }),
        new OptimizeCssAssetsPlugin({
            cssProcessor: require('cssnano'),
            cssProcessorOptions: {
                map: {
                    inline: false,
                },
                discardComments: {
                    removeAll: true
                }
            },
            canPrint: true
        })
    ]
};