Set.prototype.size

Size属性将会返回Set对象中元素的个数。

描述

size的值是一个整数，表示Set对象有多少条目。size的集合访问函数是undefined; 你不能改变这个属性。

例子

使用size

var mySet = new Set();
mySet.add(1);
mySet.add(5);
mySet.add("some text")

mySet.size; // 3

规范

Specification Status Comment

ECMAScript 2015 (6th Edition, ECMA-262)
Set.prototype.size

 Standard 初始定义

ECMAScript Latest Draft (ECMA-262)
Set.prototype.size

 Draft  

浏览器兼容

Update compatibility data on GitHub
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
size Chrome Full support 38 Edge Full support 12 Firefox Full support 19
Notes
Full support 19
Notes
Notes From Firefox 13 to Firefox 18, the size property was implemented as a Set.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.
IE Full support 11 Opera Full support 25 Safari Full support 8 WebView Android Full support 38 Chrome Android Full support 38 Firefox Android Full support 19
Notes
Full support 19
Notes
Notes From Firefox 13 to Firefox 18, the size property was implemented as a Set.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.
Opera Android Full support 25 Safari iOS Full support 8 Samsung Internet Android Full support 3.0 nodejs Full support 0.12

Legend

Full support  
Full support
See implementation notes.
See implementation notes.

参见

  1. JavaScript 标准库
  2. Set
  3. 属性
    1. Set.prototype
    2. Set.prototype.size
    3. get Set[@@species]
  4. 方法
    1. Set.prototype.add()
    2. Set.prototype.clear()
    3. Set.prototype.delete()
    4. Set.prototype.entries()
    5. Set.prototype.forEach()
    6. Set.prototype.has()
    7. Set.prototype.values()
    8. Set.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()