JavaScript实现Object的clone

前提：

JavaScript中并没有提供对象的Clone方法，采用直接赋值的方法(var a = {key:'val'}; var b = a;)有一个很大的弊端：改变b的同时会改变a。所以，实现对象的clone方法是必要的。下面给出了几种实现方法。

1.$.extend()方法

var copiedObject = jQuery.extend({},originalObject);

添加true参数实现deep copy

var copiedObject = jQuery.extend(true, {}, originalObject);

2.自定义简单的clone方法

    Object.prototype.clone = function() {
        var obj = this;
        var copy = (obj instanceof Array) ? [] : {};
        for(var attr in obj) {
            if(!obj.hasOwnProperty(attr))
                continue;
            copy[attr] = (typeof obj[attr] == 'Object') ? obj[attr].clone() : obj[attr];
        }
        return copy;
    };

    var a = {name:'Sherry', age:12, interests:['Reading', 'Traveling', 'Running']};
    var b = a.clone();

3.自定义的deep copy方法

    function clone(obj) {
        // Handle the 3 simple types, and null or undefined
        if (null == obj || "object" != typeof obj) return obj;

        // Handle Date
        if (obj instanceof Date) {
            var copy = new Date();
            copy.setTime(obj.getTime());
            return copy;
        }

        // Handle Array
        if (obj instanceof Array) {
            var copy = [];
            for (var i = 0, len = obj.length; i < len; i++) {
                copy[i] = clone(obj[i]);
            }
            return copy;
        }

        // Handle Object
        if (obj instanceof Object) {
            var copy = {};
            for (var attr in obj) {
                if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);
            }
            return copy;
        }

        throw new Error("Unable to copy obj! Its type isn't supported.");
    }

    var a = {name:'Sherry', age:12, interests:['Reading', 'Traveling', 'Running']};
    var b = clone(a);

Ref: Most elegant way to clone a JavaScript object