webpack.dev.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');

module.exports = {
    entry: {
        game: './client/index.js'
    },
    mode: 'development',
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'bundle.js'
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: "babel-loader",
                    options: {
                        presets: ['@babel/preset-env'],
                    },
                },
            },
            {
                test: /\.css$/i,
                use: [MiniCssExtractPlugin.loader, 'css-loader'],
            },
        ],
    },
    plugins: [
        new MiniCssExtractPlugin(),
        new HtmlWebpackPlugin({
            filename: 'index.html',
            template: `client/html/index.html`
        })
    ],
    optimization: {
        minimize: true,
        minimizer: [
            // For webpack@5 you can use the `...` syntax to extend existing minimizers (i.e. `terser-webpack-plugin`), uncomment the next line
            `...`,
            new CssMinimizerPlugin(),
        ],
    },
}