gulp で coffee script + browserify

browserify = require "browserify"
transform = require "vinyl-transform"
rename = require "gulp-rename"

gulp
  .src "coffee/*.coffee",
    base: "coffee/"
  .pipe transform (filename) ->
    browserify filename
      .transform {}, "coffeeify"
      .bundle()
  .pipe rename
    extname: ".js"
  .pipe gulp.dest "js/"