WeakMap.prototype.get()

get() 方法返回  WeakMap 指定的元素。

语法

wm.get(key);

参数

key
必须。 想要从  WeakMap 获取的元素的键。

返回值

返回与指定键相关联的值，如果 WeakMap 对象找不到这个键则返回 undefined。

例子

使用 get 方法 

var wm = new WeakMap();
wm.set(window, "foo");

wm.get(window); // 返回 "foo".
wm.get("baz");  // 返回 undefined.

规范

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
WeakMap.prototype.get		 Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
WeakMap.prototype.get		 Draft  

浏览器兼容性

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!

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 36 6.0 (6.0) 11 23 7.1
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support 未实现 6.0 (6.0) 未实现 未实现 8

Firefox 中的注意事项

  • Prior to SpiderMonkey 38 (Firefox 38 / Thunderbird 38 / SeaMonkey 2.35), this method threw a bug 1127827).

相关链接

  1. JavaScript 标准库
  2. WeakMap
  3. 属性
    1. WeakMap.prototype
  4. 方法
    1. WeakMap.prototype.clear()
    2. WeakMap.prototype.delete()
    3. WeakMap.prototype.get()
    4. WeakMap.prototype.has()
    5. WeakMap.prototype.set()
  5. 继承
  6. Function
  7. 属性
    1. Function.arguments
    2. Function.arity
    3. Function.caller
    4. Function.displayName
    5. Function.length
    6. Function.prototype
    7. Function.name
  8. 方法
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.isGenerator()
    5. Function.prototype.toSource()
    6. Function.prototype.toString()
  9. Object
  10. 属性
    1. Object.prototype.__count__
    2. Object.prototype.__noSuchMethod__
    3. Object.prototype.__parent__
    4. Object.prototype.__proto__
    5. 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.unwatch()
    12. Object.prototype.valueOf()
    13. Object.prototype.watch()
    14. Object.setPrototypeOf()