code: function(code, url, done) {
    var vm = require('vm')
    var sandbox = {}
    var expose = [
      'application',
      'setTimeout',
      'setInterval',
      'clearTimeout',
      'clearInterval'
    ]
  
    for (var i = 0; i < expose.length; i++) {
      sandbox[expose[i]] = global[expose[i]]
    }
  
    code = '"use strict";\n' + code
    try {
      vm.runInNewContext(code, vm.createContext(sandbox), url)
      done()
    } catch (e) {
      done(e)
    }
  }
docs: Executes the given code in a jailed environment, runs the
  corresponding callback when done
  
  @param {String} code to execute
  @param {String} url of the script (for displaying the stack)