webpack.config.js

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

Encore
    // the project directory where compiled assets will be stored
    .setOutputPath('public/build/')
    // the public path used by the web server to access the previous directory
    .setPublicPath('/build')
    .cleanupOutputBeforeBuild()
    .enableSourceMaps(!Encore.isProduction())
    // uncomment to create hashed filenames (e.g. app.abc123.css)
    .enableVersioning(Encore.isProduction())

    // uncomment to define the assets of the project
    .addEntry('js/app', './assets/js/app.jsx')
    .addStyleEntry('css/app', './assets/css/app.scss')

    // uncomment if you use Sass/SCSS files
    .enableSassLoader()

    .enableReactPreset()

    .enableSingleRuntimeChunk()

    .configureBabel(function(babelConfig) {
        return {
            ...babelConfig,
            "plugins": ["@babel/plugin-proposal-class-properties"]
        }
    })

    // uncomment for legacy applications that require $/jQuery as a global variable
    // .autoProvidejQuery()
;

module.exports = Encore.getWebpackConfig();