webpack.config.js

const Encore = require('@symfony/webpack-encore');

// Manually configure the runtime environment if not already configured yet by the "encore" command.
// It's useful when you use tools that rely on webpack.config.js file.
if (!Encore.isRuntimeEnvironmentConfigured()) {
    Encore.configureRuntimeEnvironment(process.env.NODE_ENV || 'dev');
}

Encore
    // directory where compiled assets will be stored
    .setOutputPath('public/build/')
    .setPublicPath('/build')
    .copyFiles({
        from: './node_modules/bootstrap/dist/',
        pattern: /bootstrap.min.css|bootstrap.min.js/,
        to: '[path][name].[ext]'
    })
    .copyFiles({
        from: './node_modules/@popperjs/core/dist/umd',
        pattern: /popper.min.js/,
        to: 'js/[name].[ext]'
    })

    /*
     * ENTRY CONFIG
     *
     * Each entry will result in one JavaScript file (e.g. app.js)
     * and one CSS file (e.g. app.css) if your JavaScript imports CSS.
     */
    .addEntry('app', './assets/app.js')

    // enables the Symfony UX Stimulus bridge (used in assets/bootstrap.js)
    .enableStimulusBridge('./assets/controllers.json')

    // When enabled, Webpack "splits" your files into smaller pieces for greater optimization.
    .splitEntryChunks()

    // will require an extra script tag for runtime.js
    // but, you probably want this, unless you're building a single-page app
    .enableSingleRuntimeChunk()

    /*
     * FEATURE CONFIG
     *
     * Enable & configure other features below. For a full
     * list of features, see:
     * https://symfony.com/doc/current/frontend.html#adding-more-features
     */
    .cleanupOutputBeforeBuild()
    .enableBuildNotifications()
    .enableSourceMaps(!Encore.isProduction())
    // enables hashed filenames (e.g. app.abc123.css)
    .enableVersioning(Encore.isProduction())
    // enables and configure @babel/preset-env polyfills
    .configureBabelPresetEnv((config) => {
        config.useBuiltIns = 'usage';
        config.corejs = '3.23';
    })
    .enableSassLoader()
;

module.exports = Encore.getWebpackConfig();