browserify,babelify,riotify,uglify,gzip-size build script

bundle.build.js

#!/usr/bin/env babel-node
var fs = require('fs')
  , path = require('path')
  , browserify = require('browserify')
  , babelify = require('babelify')
  , riotify = require('riotify')
  , uglify = require('uglify-js2')
  , watchify = require('watchify')
  , gzipSize = require('gzip-size')
  , source = require('vinyl-source-stream')
  , gulp = require('gulp')
  ;
var sourcePath = './path/to/source.js'
  , distPath = './public/dist'
  , distJsBasename = 'dest.js'
  , distJsPath = path.join(distPath, distJsBasename)
  , distMinJsPath = './public/dist/dest.min.js'
  ;
var b = browserify({
  entries: [sourcePath],
  cache: {},
  packageCache: {},
  plugin: [watchify]
});
b
  .require('riot', {expose: true})
  .transform(riotify)
  .transform(babelify, {presets: ["es2015"]})
  ;
b.on('update', bundle);
b.on('log', onLog);
bundle();
function bundle() {
  b
    .bundle()
    .pipe(source(distJsBasename))
    .pipe(gulp.dest(distPath))
    .on('end', bundleEnd)
    ;
}
function onLog(msg) {
  console.log(msg);
}
function bundleEnd() {
  var code = fs.readFileSync(distJsPath).toString();
  var ast = uglify.parse(code, {
    filename: distJsPath,
    topLevel: null
  });
  var stream = uglify.OutputStream();
  ast.print(stream);
  var codeMinified = stream.toString();
  fs.writeFileSync(distMinJsPath, codeMinified, 'utf8');
  var minGzipSize = gzipSize.sync(codeMinified);
  console.log('min gzip size: '+minGzipSize);
}