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