## Summary

The `WeakSet``.prototype` property represents the prototype for the `WeakSet` constructor.

`WeakSet.prototype` 属性的属性特性：
writable | false
enumerable | false
configurable | false

## Description

`WeakSet` instances inherit from `WeakSet.prototype`. You can use the constructor's prototype object to add properties or methods to all `WeakSet` instances.

## Properties

`WeakSet.prototype.constructor`
  返回构造函数即 `WeakSet` 本身.

## Methods

`WeakSet.prototype.add(value)`
  在该 `WeakSet` 对象中添加一个新元素 `value`.
`WeakSet.prototype.clear()`
  清空该 `WeakSet` 对象中的所有元素.
`WeakSet.prototype.delete(value)`
  从该 `WeakSet` 对象中删除 `value` 这个元素, 之后 `WeakSet.prototype.has(value)` 方法便会返回 `false`.
`WeakSet.prototype.has(value)`
  返回一个布尔值, 表示给定的值 `value` 是否存在于这个 `WeakSet` 中.

## Specifications

Specification | Status | Comment
--- | --- | ---
ECMAScript 2015 (6th Edition, ECMA-262) WeakSet.prototype | Standard | Initial definition.

## Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

- Desktop
- Mobile

Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari
--- | --- | --- | --- | --- | ---
Basic support | (Yes) | 未实现 bug 792439 | 未实现 | 未实现 | 未实现

Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile
--- | --- | --- | --- | --- | ---
Basic support | 未实现 | 未实现 bug 792439 | 未实现 | 未实现 | 未实现

### Chrome-specific notes

- This feature is available behind a preference. In `chrome://flags`, activate the entry “Enable Experimental JavaScript”.

## See also

- `Set.prototype`
- `WeakMap.prototype`