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

register() method registers an object with a FinalizationRegistry instance so that if the object is garbage-collected, the registry's callback may get called.

句法

registry.register(target, heldValue, [unregisterToken]);
					

参数

target

The target object to register.

heldValue

The value to pass to the finalizer for this object. This cannot be the target 对象。

unregisterToken 可选

A token that may be used with the unregister method later to unregister the target object. If provided (and not undefined ), this must be an object. If not provided, the target cannot be unregistered.

返回值

undefined .

注意事项

见 Avoid where possible and Notes on cleanup callbacks sections of the FinalizationRegistry page for important caveats.

范例

Using register

The following registers the target object referenced by target , passing in the held value "some value" and passing the target object itself as the unregistration token:

registry.register(target, "some value", target);
					

The following registers the target object referenced by target , passing in another object as the held value, and not passing in any unregistration token (which means target can't be unregistered):

registry.register(target, {"useful": "info about target"});
					

规范

规范
WeakRefs The definition of 'FinalizationRegistry.prototype.register' 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
register	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

• FinalizationRegistry

元数据

• 最后修改： Jul 13, 2020

相关话题

1. 标准内置对象
2. FinalizationRegistry
3. 方法
   1. FinalizationRegistry.prototype.register()
   2. FinalizationRegistry.prototype.unregister()
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()