Map.prototype.clear()

clear()方法会移除Map对象中的所有元素。

语法

myMap.clear();

返回值

undefined.

示例

调用clear方法

var myMap = new Map();
myMap.set("bar", "baz");
myMap.set(1, "foo");

myMap.size;       // 2
myMap.has("bar"); // true

myMap.clear();

myMap.size;       // 0
myMap.has("bar")  // false

规范

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

浏览器兼容

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
clearChrome Full support 38Edge Full support 12Firefox Full support 19IE Full support 11Opera Full support 25Safari Full support 8WebView Android Full support 38Chrome Android Full support 38Firefox Android Full support 19Opera Android Full support 25Safari iOS Full support 8Samsung Internet Android Full support 3.0nodejs Full support 0.12

Legend

Full support  
Full support

相关链接

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  1. JavaScript 标准库
  2. Map
  3. 属性
    1. Map.prototype
    2. Map.prototype.size
    3. Map.prototype[@@toStringTag]
    4. 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. 属性
    1. Function.arguments
    2. Function.arity
    3. Function.caller
    4. Function.displayName
    5. Function.length
    6. Function.name
    7. Function.prototype
  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()