javascript - WeakMap

Question

  const weakm = new WeakMap();
  let keyObject = {id : 1};
  const valObject = {score : 100};
  weakm.set(keyObject,valObject);
  console.log(weakm.get(keyObject));
  keyObject = null;
  console.log(weakm);
  console.log(weakm.get(keyObject));

打印结果：

为什么打印weakm还有键 {id：1}，各位赐教

Answer 1

你这问题好比：
var a={id:1};
b=a;
a=null;
console.log(b);