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JS--判断是对象还是数组

news 2025/8/11 8:04:34

原文网址：JS--判断是对象还是数组-CSDN博客

简介

本文介绍JS判断是否是对象或者数组的方法。

法1：instanceof

var arr1 = [1,2,3,4];
var arr2 = [];
var obj = {};
console.log(arr1 instanceof Array);   //true
console.log(arr2 instanceof Array);   //true
console.log(obj instanceof Array);    //false

法2：对象的constructor属性

var arr1 = [1,2,3,4];
var arr2 = [];
var obj = {};
console.log(arr1.constructor);  //Array
console.log(arr2.constructor);  //Array
console.log(obj.constructor);   //Object

可以这样判断：

return arr1.constructor === Array;

法3：Object.prototype.toString.call

console.log(Object.prototype.toString.call());         //undefined
console.log(Object.prototype.toString.call("123"));    //string
console.log(Object.prototype.toString.call(123));      //numberconsole.log(Object.prototype.toString.call([1,2,3]));  //Array
console.log(Object.prototype.toString.call({}));       //Object

法4：ES5中的Array.isArray

var arr1 = [1,2,3,4];
var arr2 = [];
var obj = {};
console.log(Array.isArray(arr1));    //true
console.log(Array.isArray(arr2));    //true
console.log(Array.isArray(obj));     //false

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