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• 描述
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

Map[@@species] accessor property returns the Map 构造函数。

描述

The species accessor property returns the default constructor for Map objects. Subclass constructors may over-ride it to change the constructor assignment.

范例

Species in ordinary objects

The species property returns the default constructor function, which is the Map constructor for Map 对象：

Map[Symbol.species]; // function Map()
					

Species in derived objects

In a derived collection object (e.g. your custom map MyMap ), the MyMap species is the MyMap constructor. However, you might want to overwrite this, in order to return parent Map objects in your derived class methods:

class MyMap extends Map {
  // Overwrite MyMap species to the parent Map constructor
  static get [Symbol.species]() { return Map; }
}
					

规范

规范
ECMAScript (ECMA-262) The definition of 'get Map [ @@species ]' 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
@@species	Chrome 51	Edge 13	Firefox 41	IE No	Opera 38	Safari 10	WebView Android 51	Chrome Android 51	Firefox Android 41	Opera Android 41	Safari iOS 10	Samsung Internet Android 5.0	nodejs 6.5.0 6.5.0 6.0.0 Disabled Disabled From version 6.0.0: this feature is behind the --harmony 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

• Map
• Symbol.species

元数据

• 最后修改： May 21, 2020

相关话题

1. 标准内置对象
2. Map
3. 特性
   1. Map.prototype.size
   2. Map.prototype[@@toStringTag]
   3. get Map[@@species]
4. 方法
   1. Map.prototype.clear()
   2. Map.prototype.delete()
   3. Map.prototype.entries()
   4. Map.prototype.forEach()
   5. Map.prototype.get()
   6. Map.prototype.has()
   7. Map.prototype.keys()
   8. Map.prototype.set()
   9. Map.prototype.values()
   10. Map.prototype[@@iterator]()
5. 继承：
6. Function
7. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
8. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
9. Object
10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
11. 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()