在此页

• 句法
• 注意事项
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

deref method returns the WeakRef instance's target object, or undefined if the target object has been garbage-collected.

句法

obj = ref.deref();
					

返回值

The target object of the WeakRef, or undefined if the object has been garbage-collected.

注意事项

见 Notes on WeakRefs section of the WeakRef page for some important notes.

范例

Using deref

见 范例 section of the WeakRef page for the complete example.

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

规范
WeakRefs The definition of 'WeakRef.prototype.deref()' in that specification.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
deref	Chrome 84	Edge 84	Firefox 79	IE No	Opera No	Safari No	WebView Android 84	Chrome Android 84	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android No	nodejs 13.0.0 Disabled 13.0.0 Disabled Disabled From version 13.0.0: this feature is behind the --harmony-weak-refs runtime flag.

图例

完整支持

完整支持

不支持

不支持

用户必须明确启用此特征。

用户必须明确启用此特征。

另请参阅

• WeakRef

元数据

• 最后修改： Jul 6, 2020

相关话题

1. 标准内置对象
2. WeakRef
3. 方法
   1. WeakRef.prototype.deref()
4. 继承：
5. Function
6. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
7. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
8. Object
9. 特性
   1. Object.prototype.__proto__
   2. Object.prototype.constructor
10. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()