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。

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

mySet.size; // 3

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) Set.prototype.size	Standard	初始定义
ECMAScript (ECMA-262) Set.prototype.size	Living Standard

	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