Failed to run signUp function in cloud code #732

Parse.Cloud.define('register',(req,res) => {
  var email     = req.params.email
  var password  = req.params.password
  var name      = req.params.name

  var user = new Parse.User()
  user.set('email',email)
  user.set('password',password)
  user.set('username',name)

  user.signUp(null, {
    success: (user) => {
      res.success('success')
    },
    error: (user,error) => {
      res.error(error)
    }
  })