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

额，可能是浏览器为了让你方便查看里面的值吧，所以一直记录了下来，不过在 node 中是不会打印任何值的