獲取與金鑰關聯的值

Created: November-22, 2018

要獲取與金鑰關聯的值，請使用 .get() 方法。如果沒有與該鍵相關聯的值，則返回 undefined。

const obj1 = {},
      obj2 = {};

const weakmap = new WeakMap([[obj1, 7]]);
console.log(weakmap.get(obj1)); // 7
console.log(weakmap.get(obj2)); // undefined