WeakMap.prototype.delete()

const weakmap1 = new WeakMap();
const object1 = {};

weakmap1.set(object1, 42);

console.log(weakmap1.delete(object1));
// Expected output: true

console.log(weakmap1.has(object1));
// Expected output: false

weakMapInstance.delete(key)

const wm = new WeakMap();
wm.set(window, "foo");

wm.delete(window); // 返回 true。成功删除。

wm.has(window); // 返回 false。WeakMap 中已经不存在 window 对象。