webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');

const isProd = (process.env.NODE_ENV === 'production');

module.exports = {
    mode: isProd ? 'production' : 'development',
    devtool: isProd ? 'source-map' : 'eval-source-map',
    entry: {
        app: ['./src/index.js']
    },
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: '[name].bundle.js'
    },
    resolve: {
        extensions: ['.js']
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: [/node_modules/, path.resolve(__dirname, 'src/assets')],
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env']
                    }
                }
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './src/index.html',
            path: path.resolve(__dirname, 'dist'),
            filename: 'index.html',
            inject: 'head',
            scriptLoading: 'blocking',
            hash: true
        }),
        new CopyWebpackPlugin({ patterns: [{ from: 'src/assets', to: 'assets' }] })
    ]
};