symfony/webpack-encore-bundle

assets/app.js

/*
 * Welcome to your app's main JavaScript file!
 *
 * We recommend including the built version of this JavaScript file
 * (and its CSS file) in your base layout (base.html.twig).
 */

// any CSS you import will output into a single css file (app.css in this case)
import './styles/app.css';

// start the Stimulus application
import './bootstrap';

assets/bootstrap.js

import { startStimulusApp } from '@symfony/stimulus-bridge';

// Registers Stimulus controllers from controllers.json and in the controllers/ directory
export const app = startStimulusApp(require.context(
    '@symfony/stimulus-bridge/lazy-controller-loader!./controllers',
    true,
    /\.[jt]sx?$/
));

// register any custom, 3rd party controllers here
// app.register('some_controller_name', SomeImportedController);

assets/controllers.json

{
    "controllers": [],
    "entrypoints": []
}

assets/controllers/hello_controller.js

import { Controller } from '@hotwired/stimulus';

/*
 * This is an example Stimulus controller!
 *
 * Any element with a data-controller="hello" attribute will cause
 * this controller to be executed. The name "hello" comes from the filename:
 * hello_controller.js -> "hello"
 *
 * Delete this file or adapt it for your use!
 */
export default class extends Controller {
    connect() {
        this.element.textContent = 'Hello Stimulus! Edit me in assets/controllers/hello_controller.js';
    }
}

assets/styles/app.css

body {
    background-color: lightgray;
}

config/packages/webpack_encore.yaml

webpack_encore:
    # The path where Encore is building the assets - i.e. Encore.setOutputPath()
    output_path: '%kernel.project_dir%/public/build'
    # If multiple builds are defined (as shown below), you can disable the default build:
    # output_path: false

    # Set attributes that will be rendered on all script and link tags
    script_attributes:
        defer: true
        # Uncomment (also under link_attributes) if using Turbo Drive
        # https://turbo.hotwired.dev/handbook/drive#reloading-when-assets-change
        # 'data-turbo-track': reload
    # link_attributes:
        # Uncomment if using Turbo Drive
        # 'data-turbo-track': reload

    # If using Encore.enableIntegrityHashes() and need the crossorigin attribute (default: false, or use 'anonymous' or 'use-credentials')
    # crossorigin: 'anonymous'

    # Preload all rendered script and link tags automatically via the HTTP/2 Link header
    # preload: true

    # Throw an exception if the entrypoints.json file is missing or an entry is missing from the data
    # strict_mode: false

    # If you have multiple builds:
    # builds:
        # pass "frontend" as the 3rg arg to the Twig functions
        # {{ encore_entry_script_tags('entry1', null, 'frontend') }}

        # frontend: '%kernel.project_dir%/public/frontend/build'

    # Cache the entrypoints.json (rebuild Symfony's cache when entrypoints.json changes)
    # Put in config/packages/prod/webpack_encore.yaml
    # cache: true

framework:
    assets:
        json_manifest_path: '%kernel.project_dir%/public/build/manifest.json'

#when@prod:
#    webpack_encore:
#        # Cache the entrypoints.json (rebuild Symfony's cache when entrypoints.json changes)
#        # Available in version 1.2
#        cache: true

#when@test:
#    webpack_encore:
#        strict_mode: false

package.json

{
    "devDependencies": {
        "@hotwired/stimulus": "^3.0.0",
        "@symfony/stimulus-bridge": "^3.2.0",
        "@symfony/webpack-encore": "^3.0.0",
        "core-js": "^3.23.0",
        "regenerator-runtime": "^0.13.9",
        "webpack-notifier": "^1.15.0"
    },
    "license": "UNLICENSED",
    "private": true,
    "scripts": {
        "dev-server": "encore dev-server",
        "dev": "encore dev",
        "watch": "encore dev --watch",
        "build": "encore production --progress"
    }
}

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/')
    // public path used by the web server to access the output path
    .setPublicPath('/build')
    // only needed for CDN's or sub-directory deploy
    //.setManifestKeyPrefix('build/')

    /*
     * 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())

    .configureBabel((config) => {
        config.plugins.push('@babel/plugin-proposal-class-properties');
    })

    // enables @babel/preset-env polyfills
    .configureBabelPresetEnv((config) => {
        config.useBuiltIns = 'usage';
        config.corejs = 3;
    })

    // enables Sass/SCSS support
    //.enableSassLoader()

    // uncomment if you use TypeScript
    //.enableTypeScriptLoader()

    // uncomment if you use React
    //.enableReactPreset()

    // uncomment to get integrity="..." attributes on your script & link tags
    // requires WebpackEncoreBundle 1.4 or higher
    //.enableIntegrityHashes(Encore.isProduction())

    // uncomment if you're having problems with a jQuery plugin
    //.autoProvidejQuery()
;

module.exports = Encore.getWebpackConfig();