build.js

#!/usr/bin/env node

/**
 * Process the client side application using babelify and browserify.
 */

if (!process.env.CLIENT_PATH || !process.env.SERVER_PATH) {
  throw 'CLIENT_PATH and SERVER_PATH is required.'
}

const UglifyJS = require('uglify-js');
const fs = require('fs');
const browserify = require('browserify');
const watchify = require('watchify');

const entry = process.env.CLIENT_PATH + '/js/main.js';
const output = process.env.SERVER_PATH + '/public/js/app.js';
const outputMin = process.env.SERVER_PATH + '/public/js/app.min.js';

console.log('Starting app.js build. Environment: ' + process.env.NODE_ENV);

const b = browserify(entry, {
  debug: true,
  sourceMaps: true,
  cache: {},
  packageCache: {},
  plugin: [process.env.WATCH ? watchify : null],
  basedir: process.env.CLIENT_PATH
})
  .transform('babelify', {
    plugins: [
      process.env.SERVER_PATH + '/babel-plugins/babelRelayPlugin',
      'transform-decorators-legacy',
      'transform-class-properties'
    ],
    presets: [
      'es2015',
      'react'
    ]
  });

function bundle() {
  const stream = fs.createWriteStream(output);

  const onComplete = (function() {
    const begin = Date.now();

    return function() {
      console.log('Build complete in ' + (Date.now() - begin) / 1000 + 'secs');
    };
  })();

  b.bundle().pipe(stream)

  stream.on('finish', function() {
    if (process.env.NODE_ENV === 'production') {
      console.log('Complete, now compressing because production.');

      const stream2 = fs.createWriteStream(outputMin);

      const minified = UglifyJS.minify([output], {
        compress: {
          dead_code: true
        }
      });

      stream2.on('finish', function() {
        onComplete();
      });

      stream2.write(minified.code);
    } else {
      console.log('All done! (dev mode - not compressing)');
      onComplete();
    }
  });
}

bundle();

if (process.env.WATCH) {
  b.on('update', bundle);
}