Precompile .handlebars templates with Jake (nodejs)

Jakefile.js

var fs = require('fs')
var vm = require('vm')

var handlebarsjs = fs.readFileSync('path/to/handlebars.js', 'utf8')
var emberjs = fs.readFileSync('path/to/ember.js', 'utf8')
var templatesDir = 'path/to/template/dir'

desc('Compile all .handlebars templates')
task({ 'handlebars': [] }, function () {
  process.stdout.write('Compiling .handlebars templates')
  var files = fs.readdirSync(templatesDir)
  var i
  for (i = 0; i < files.length; i++) {
    if (/\.handlebars$/.test(files[i])) {
      compileHandlebarsTemplate(templatesDir + '/' + files[i])
      process.stdout.write('.')
    }
  }
  console.log('done')
})


function compileHandlebarsTemplate(file, onComplete) {
  //dummy jQuery
  var jQuery = function () { return jQuery }
  jQuery.ready = function () { return jQuery }
  jQuery.inArray = function () { return jQuery }
  jQuery.jquery = "1.7.1"
  jQuery.event = { fixHooks: {} }

  //dummy DOM element
  var element = {
    firstChild: function () { return element },
    innerHTML: function () { return element }
  }

  var sandbox = {
    // DOM
    document: {
      createRange: false,
      createElement: function () { return element }
    },

    // Console
    console: console,

    // jQuery
    jQuery: jQuery,
    $: jQuery,

    // handlebars template to compile
    template: fs.readFileSync(file, 'utf8'),

    // compiled handlebars template
    templatejs: null
  }

  // window
  sandbox.window = sandbox

  // create a context for the vm using the sandbox data
  var context = vm.createContext(sandbox)

  // load Handlebars and Ember into the sandbox
  vm.runInContext(handlebarsjs, context, 'ember.js')
  vm.runInContext(emberjs, context, 'ember.js')

  //compile the handlebars template inside the vm context
  vm.runInContext('templatejs = Ember.Handlebars.precompile(template).toString()', context)

  var fileName = path.basename(file)
  var namedTemplateJs = 'Ember.TEMPLATES["' +
    fileName.replace(/.handlebars/, '') +
    '"] = Ember.Handlebars.template(' + context.templatejs + ');'

  //extract the compiled template from the vm context and save to .js file,
  //implicitely adding template to Ember.TEMPLATES when it is required
  fs.writeFileSync(file.replace(/\.handlebars$/, '.js'), namedTemplateJs, 'utf8')
}

• This is an extraction of a larger jakefile (https://github.com/mde/jake) so I hope I haven't missed anything.
• The compileHandlebarsTemplate function should work without jake.
• This sample could be more efficient, especially if emberjs is not re-evaluated on each call, but it seems fast enough.
• Unlike the original example by @wagenet this sample will compile each .handlebars file to its own .js file (this is better for my build workflow), if you want to merge all output to a single file then it should be easy to modify.

Added line:

jQuery.event = { fixHooks: {} }

to fix recently introduced emberjs dependency on jQuery.event object.