Gulp, browserify, babelify, source maps, babel, es6

gulpfile.js

'use strict';

var gulp = require('gulp');
var $ = require('gulp-load-plugins')();
var source = require('vinyl-source-stream');
var babelify = require('babelify');
var browserify = require('browserify');
var watchify = require('watchify');

var dependencies = [
  'jquery'
];

gulp.task('browserify-vendor', function(){
  return browserify()
    .require(dependencies)
    .bundle()
    .pipe(source('vendor.js'))
    .pipe($.streamify($.uglify({ mangle: false })))
    .pipe(gulp.dest('public/js'));
});

gulp.task('browserify', function(){
  return browserify(['public/scripts/app.js', 'public/scripts/app2.js'], {debug: true}) // debug: true добавляет инлайн source maps
    .external(dependencies)
    .transform(babelify)
    .bundle()
    .pipe(source('index.js'))
    .pipe(gulp.dest('public/js'));
});

gulp.task('default', ['browserify-vendor', 'browserify']);