Generator 的 this

  1. function* hello(){
  2.   this.name = "world";
  3.   this.say = function(){
  4.     return this; // otherThis
  5.   }
  6.   return this; // oneThis
  7. }
  9. let gen = hello.call(hello.prototype); // 必须
  11. let oneThis = gen.next().value;
  12. let otherThis = gen.say();
  14. oneThis === otherThis // false
  15. otherThis === gen // true
  16. oneThis === otherThis.__proto__ // true
  17. oneThis === hello.prototype // true
  18. otherThis instanceof hello // true
  19. oneThis.name // world
  20. otherThis.name // world

由上代码可以看出两个各方式返回的this并不是都代表hello函数的实例；其中oneThis指向hello函数的原型hello.prototype，otherThis指向hello的实例