WeakRef.prototype.deref()
WeakRef
实例的 deref()
方法返回此 WeakRef
的目标值,如果目标值已被垃圾收集,则返回 undefined
。
¥The deref()
method of WeakRef
instances returns this WeakRef
's target value, or undefined
if the target value has been garbage-collected.
语法
参数
返回值
¥Return value
WeakRef 的目标值,可以是对象,也可以是 未注册符号。如果该值已被垃圾回收,则返回 undefined
。
¥The target value of the WeakRef, which is either an object or a non-registered symbol. Returns undefined
if the value has been garbage-collected.
描述
¥Description
请参阅 WeakRef
页的 关于 WeakRef 的注释 部分了解一些重要说明。
¥See the Notes on WeakRefs section of the WeakRef
page for some important notes.
示例
使用 deref()
¥Using deref()
¥See the Examples
section of the WeakRef
page for the complete example.
js
const tick = () => {
// Get the element from the weak reference, if it still exists
const element = this.ref.deref();
if (element) {
element.textContent = ++this.count;
} else {
// The element doesn't exist anymore
console.log("The element is gone.");
this.stop();
this.ref = null;
}
};
规范
Specification |
---|
ECMAScript Language Specification # sec-weak-ref.prototype.deref |
浏览器兼容性
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也可以看看
¥See also