webpack.mix.js

const mix = require('laravel-mix');
require('laravel-mix-polyfill');

mix.webpackConfig({
    module: {
        rules: [{
            test: /\.jsx?$/,
            exclude: /(bower_components)/,
            use: [
                {
                    loader: 'babel-loader',
                    options: mix.config.babel()
                },
            ],
        }],
    }
});

mix.setPublicPath('./assets')
    .js('./src/js/frontend/main.js', './assets/js/frontend')
    // .babel('./assets/js/frontend/main.js', './assets/js/frontend/main.js')
    .js('./src/js/admin/admin.js', './assets/js/admin')
    .js('./src/js/backend/backend.js', './assets/js/backend')
    .sass('./src/scss/frontend/frontend.scss', './assets/css')
    .sass('./src/scss/builder/builder.scss', './assets/css')
    .sass('./src/scss/backend/backend.scss', './assets/css')
    .sass('./src/scss/admin/admin.scss', './assets/css')
    .polyfill({
        enabled: true,
        useBuiltIns: 'usage',
        targets: {'ie': 11}
    })
    .options({
        processCssUrls: false,
        postCss: [
            require('autoprefixer'),
            require('css-mqpacker')
        ],
    });

// disable mix-manifest.json
Mix.manifest.refresh = _ => void 0;