How to determine if an object is an array in jquery-JS Tutorial-php.cn

How to determine if an object is an array in jquery

coldplay.xixi

Release： 2020-11-19 11:46:29

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Jquery method to determine whether an object is an array: Pass the variable [$.isArray()] that needs to be determined into the method, and the syntax is [$.isArray( object ) / jQuery.isArray( object ) ].

How to determine if an object is an array in jquery

jquery method to determine whether an object is an array:

$.isArray() The function is used to determine whether the specified parameter is an array. Just pass the variables that need to be judged into the method.

Syntax$.isArray(object) / jQuery.isArray(object)

Parameters object Any type Any value that needs to be judged.

Return value true/false

<!DOCTYPE html>
<html>
<head>
<title>jq中的isArray方法分析</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<div class="warp">
</div>
<script type="text/javascript">
//下面是从jquery 1.9中抽出来的源码
var class2type = {},core_toString = class2type.toString;
//在firefox chrome IE9 IE10中都支持 Array.isArray
//使用方法 Array.isArray([])   返回 true
//但是在IE7或更低版是不支持的
var isArray = Array.isArray || function( obj ) {
        return type(obj) === "array";
};
/*
这一行也不能忽略  948行
jQuery.each("Boolean Number String Function Array Date RegExp Object Error".split(" "), function(i, name) {
    class2type[ "[object " + name + "]" ] = name.toLowerCase();
});
一开始没关注这段代码，结果弄了半天 type([])都是返回 object
那这段代码用JS写出来如下
*/
var arr = "Boolean Number String Function Array Date RegExp Object Error".split(" ");
for(var i in arr){
    class2type[ "[object " + arr[i] + "]" ] = arr[i].toLowerCase();
};
var  type = function( obj ) {
    if ( obj == null ) {
        return String( obj );
    }
    return typeof obj === "object" || typeof obj === "function" ?
        class2type[ core_toString.call(obj) ] || "object" :
        typeof obj;
    // 相当于return (typeof obj === "object" || typeof obj === "function")?(class2type[ core_toString.call(obj) ] || "object"): typeof obj;
};
//这样就可以了
//后来在网上搜索了一下 发现了网上提供的方案是   return Object.prototype.toString.call(obj) === &#39;[object Array]&#39;;
//详情查看 http://sofish.de/1591
</script>
</body>
</html>

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