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')
    // the public path you will use in Symfony's asset() function - e.g.
    // asset('build/some_file.js')
    .setManifestKeyPrefix('build/')

    .cleanupOutputBeforeBuild()
    .enableSourceMaps(!Encore.isProduction())

    // the following line enables hashed filenames (e.g. app.abc123.css)
    .enableVersioning(Encore.isProduction())

    // Enable Sass compiler.
    .enableSassLoader()

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

module.exports = Encore.getWebpackConfig();