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javascript 对象的复制

1.　　jQuery has a method that can be used to deep-clone objects, the$.extend() function. Let’s take a look at how it can be used:

var bob = {
    name: "Bob",
    age: 32
};
  
var bill = $.extend(true, {}, bob);
bill.name = "Bill";
  
console.log(bob);
console.log(bill);

注意：Pretty handy, eh? This method is a little slower than the JSON exploit, but that shouldn’t really be a problem when you’re only doing a few clones. If you’re doing hundreds or thousands of clones, it might be time to think about the JSON exploit or another solution.

2.　　 A clever exploit of the JSON library to deep-clone objects

We can exploit the JSON library for a rather fast way of deep-cloning objects. Check it out:

var bob = {
    name: "Bob",
    age: 32
};
  
var bill = (JSON.parse(JSON.stringify(bob)));
bill.name = "Bill";
  
console.log(bob);
console.log(bill);

3.　　tipJS中的一个方法，也不错，不过我自己还没完全理解这个方法的独到之处（或者说这个方法的用途）。

util__.cloneObject = function(obj, isFlat){
        var newObj, k;
        if (obj == null || typeof obj != "object") return obj;
        if (!isFlat) {
            newObj = (obj instanceof Array) ? [] : {};
            for (k in obj) {
                if (typeof obj[k] == "object") newObj[k] = util__.cloneObject(obj[k], false);
                else newObj[k] = obj[k];
            }
            return newObj;
        } else return __cloneObjN(obj);
    };
 
 
var __cloneObjN = function(target) {
        if (util__.isFunction(Object.create)) __cloneObjN = function(o) {   return Object.create(o); };
        else {
            __cloneObjN = function(o) {
                function F() {};
                F.prototype = o;
                return new F;
            };
        }
        return __cloneObjN(target);
    };