watchifying multiple bundles with gulp

gistfile1.js

var gulp         = require('gulp');
var filter       = require('gulp-filter');
var source       = require('vinyl-source-stream');
var gutil        = require('gulp-util');
var path         = require('path');
var colors       = require('colors');


var createBundle = function(file) {
  var method =  (env.prebuild || env.stage || env.production) ? 'browserify' : 'watchify';

  var bundler = require('browserify')({
    cache: {} 
    , packageCache: {}
    , fullPaths: true
    , entries: [file.path]
    , debug: true
  });

  var rebundle = function() {

    var startTime = new Date().getTime();

    gutil.log(( method + 'ing').magenta + ' : ' + file.path.yellow);

    // uglify-ify it?
    if (env.prebuild || env.production) {
      gutil.log(('uglify-ify-ing').magenta + ' : ' + file.path.yellow);
      bundler.transform({
        global: true,
        source_map: false
      },require('uglifyify'));
    }

    bundler
      .external('backbone')
      .external('underscore')
      .external('underscore.string')
      .external('redefLibs')
      // elsify stream
      .transform(require('ejsify'))
      .transform(require('brfs'))

      // attempting to hijack the errors
      .on('error', function(args){
        gutil.log(args);
      })

      // log time
      .on('end', function(){
        var time = (new Date().getTime() - startTime) / 1000;
        gutil.log( file.path.yellow + ' b-fied ' + time.magenta + ' s' );         
      })

      // bundle it.
      .bundle()
      // return bundled content to a stream of the same name as original
      .pipe(source(path.basename(file.path)))
      
      // keep it organized by app name
      .pipe( gulp.dest((env.prebuild ? 'dist/static/' : './static/') + path.dirname(file.path).replace( __dirname + '/apps/', '' )));

      
  };
  // watch.
  
  if(!env.stage && !env.production && !env.prebuild ) {
    bundler = require('watchify')(bundler);
    bundler.on('update', rebundle);
  }  

  // init
  return rebundle();
};


gulp.task('browserify', function(){
  // there are about 18 sources, and 35 dependencies total
  return gulp.src( './apps/**/+(client|dev)*.js')
    
    // pull each file out of the stream
    .pipe(require('gulp-tap')(function(file, t) {
      createBundle(file);
    }));
});