gulpfile.coffee

gulp       = require 'gulp'
util       = require 'gulp-util'
source     = require 'vinyl-source-stream'
browserify = require 'browserify'
watchify   = require 'watchify'

gulp.task 'watch', ->
  bundler = watchify browserify
    entries: ['./src/index.coffee']
    extensions: ['coffee']
    transform: ['coffeeify']
    debug: true

  bundle = ->
    util.log 'index.coffee has compiled.'
    bundler
      .bundle()
      .on 'error', (err) -> util.log 'Browserify Error: ', err
      .pipe source 'app.js'
      .pipe gulp.dest './public'

  bundler.on 'update', bundle

  bundle()

gulp.task 'default', ['watch']