code: function compileBundle (bundle, dest) {
    return bundle.bundle()
      .on('error', gutil.log.bind(gutil, 'Browserify Error'))
      .pipe(source(dest))
      .pipe(buffer()) // buffer file contents (is this necessary?)
      .pipe(gulp.dest(dir.prod + 'scripts/'))
  }
docs: Compile a browserify bundle (used by multiple tasks)