browserify, babel, gulp, glob, vinyl-source-stream, uglify

gulpfile.js

/* 
  npm install gulp gulp-load-plugins gulp-uglify
  npm install browserify babelify glob vinyl-source-stream vinyl-buffer
  
  More examples: https://github.com/gulpjs/gulp/tree/master/docs/recipes
*/

var gulp = require('gulp')
var $ = require('gulp-load-plugins')()
var browserify = require('browserify')
var babelify = require('babelify')
var glob = require('glob')
var source = require('vinyl-source-stream')
var buff = require('vinyl-buffer')

gulp.task('browserify', function () {
  var files = glob.sync('./app/scripts/**/*.js');

  return browserify({
      entries: files,
      debug: true
    })
    .transform(babelify)
    .bundle()
    .pipe(source('bundle.js'))
    .pipe(buff())
    .pipe($.uglify())
    .pipe(gulp.dest('dest/scripts'));
});

/* Do not use vinyl-transform https://github.com/substack/node-browserify/issues/1191 */