单选题

关于ES6的使用以下描述错误的是？

Question

A. const a = 1
const b = 2
const map = {a, b}

B. enum TYPE {
  OK,
  YES
}

C. class A {
  constructor (a) {
  this.a = a
  }
}
class AA extends A {
  constructor (a, b) {
    super(a)
    this.b = b
  }
  toString () {
    return this.a + '' + this.b
  }
}

D. function* greet(){
 yield "How"
 yield "are"
 yield "you"
}
var greeter = greet()
console.log(greeter.next().value)
console.log(greeter.next().value)
console.log(greeter.next().value)