test.js

// systemjs.config.js
System.config({
    baseURL: "./",
    defaultJSExtensions: true,
    transpiler: 'babel',
    babelOptions: {
        'presets': ['es2015']
    }
});


// build.js
'use strict';

const Builder = require('systemjs-builder');

const builder = new Builder();

builder.loadConfig('systemjs.config.js')
    .then(function build() {
        builder.buildStatic('./main.js', './build/app.js')
            .then(function onSuccess() {
                console.log('Build complete');
            })
            .catch(function onError(err) {
                console.log('Build error');
                console.log(err);
            });
    });
    
    
// main.js
const sender = 'Johan';
const message = `Hello from ${sender}`;