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Table of Contents

  1. 概述
  2. 语法
    1. 参数
  3. 描述
  4. 示例
  5. 兼容性
  6. if (!Object.is) { Object.is = function(v1, v2) { if (v1 === 0 && v2 === 0) return 1 / v1 === 1 / v2; if (v1 !== v1) return v2 !== v2; return v1 === v2; }; }
  7. 浏览器兼容性
  • Tags
  • 文件

This is an experimental technology, part of the Harmony (EcmaScript 6) proposal.
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future version of browsers as the spec changes.

概述

判断两个值是否真正是同一个值.

Method of Object
Implemented in JavaScript 1.8.5+
ECMAScript Edition ECMAScript 6th Edition

语法

var isSame = Object.is(value1,value2)

参数

value1
需要比较的第一个值
value1
需要比较的第二个值

描述

类似于严格相等===运算符,除了两个特例情况:就是NaN和NaN比较,以及+0和-0比较.

示例

Object.is("foo","foo");     // true
Object.is(window,window);   // true

Object.is("foo","bar");     // false
Object.is([],[]);           // false

//两个特例
Object.is(0,-0);            // false
Object.is(NaN,0/0);         // true

兼容性

if (!Object.is) { Object.is = function(v1, v2) { if (v1 === 0 && v2 === 0) return 1 / v1 === 1 / v2; if (v1 !== v1) return v2 !== v2; return v1 === v2; }; }

 

浏览器兼容性

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support Not supported

22.0 (22)

 Not supported Not supported Not supported
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported 22.0 (22) Not supported Not supported Not supported