用jQuery和JavaScript深度復制JSON對象的方法
你有時可能需要復制一個JSON對象，jQuery提供了的extend方法以前是無法進行深度復制的，不過現在也已經支持了：
// Shallow copy
var newObject = jQuery.extend({}, oldObject);
// Deep copy
var newObject = jQuery.extend(true, {}, oldObject);</pre>
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StackOverFlow的一位網友提供了一個深度復制的函數
Array.prototype.clone = function(doDeepCopy) {
if(doDeepCopy) {
var encountered = [{
a : this,
b : []
}];
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var item,
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levels = [{a:this, b:encountered[0].b, i:0}],
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level = 0,
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i = 0,
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len = this.length;
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<div>
</div>
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while(i < len) {
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item = levels[level].a[i];
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if(Object.prototype.toString.call(item) === "[object Array]") {
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for(var j = encountered.length - 1; j >= 0; j--) {
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if(encountered[j].a === item) {
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levels[level].b.push(encountered[j].b);
</div>
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break;
</div>
<div>
}
</div>
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}
</div>
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if(j < 0) {
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encountered.push(j = {
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a : item,
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b : []
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});
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levels[level].b.push(j.b);
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levels[level].i = i + 1;
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levels[++level] = {a:item, b:j.b, i:0};
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i = -1;
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len = item.length;
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}
</div>
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}
</div>
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else {
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levels[level].b.push(item);
</div>
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}
</div>
<div>
</div>
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if(++i == len && level > 0) {
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levels.pop();
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i = levels[--level].i;
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len = levels[level].a.length;
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}
</div>
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}
</div>
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</div>
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return encountered[0].b;
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}
</div>
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else {
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return this.slice(0);
</div>
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}
</div>
<div>
};
</div>
</pre>
不過此函數是加到Array對象原型上的，這意味著你使用 for in 枚舉array數組時也會枚舉出這個方法。這里有一個函數版本：
function clone(item) {
if (!item) { return item; } // null, undefined values check
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var types = [ Number, String, Boolean ],
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result;
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</div>
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// normalizing primitives if someone did new String('aaa'), or new Number('444');
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types.forEach(function(type) {
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if (item instanceof type) {
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result = type( item );
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}
</div>
<div>
});
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</div>
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if (typeof result == "undefined") {
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if (Object.prototype.toString.call( item ) === "[object Array]") {
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result = [];
</div>
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item.forEach(function(child, index, array) {
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result[index] = clone( child );
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});
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} else if (typeof item == "object") {
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// testing that this is DOM
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if (item.nodeType && typeof item.cloneNode == "function") {
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var result = item.cloneNode( true );
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} else if (!item.prototype) { // check that this is a literal
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if (item instanceof Date) {
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result = new Date(item);
</div>
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} else {
</div>
<div>
// it is an object literal
</div>
<div>
result = {};
</div>
<div>
for (var i in item) {
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<div>
result[i] = clone( item[i] );
</div>
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}
</div>
<div>
}
</div>
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} else {
</div>
<div>
// depending what you would like here,
</div>
<div>
// just keep the reference, or create new object
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if (false && item.constructor) {
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// would not advice to do that, reason? Read below
</div>
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result = new item.constructor();
</div>
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} else {
</div>
<div>
result = item;
</div>
<div>
}
</div>
<div>
}
</div>
<div>
} else {
</div>
<div>
result = item;
</div>
<div>
}
</div>
<div>
}
</div>
<div>
</div>
<div>
return result;
</div>
<div>
}
</div>
<div>
</div>
<div>
var copy = clone({
</div>
<div>
one : {
</div>
<div>
'one-one' : new String("hello"),
</div>
<div>
'one-two' : [
</div>
<div>
"one", "two", true, "four"
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]
</div>
<div>
},
</div>
<div>
two : document.createElement("div"),
</div>
<div>
three : [
</div>
<div>
{
</div>
<div>
name : "three-one",
</div>
<div>
number : new Number("100"),
</div>
<div>
obj : new function() {
</div>
<div>
this.name = "Object test";
</div>
<div>
}
</div>
<div>
}
</div>
<div>
]
</div>
<div>
})
</div>
</pre>
其實深度復制JavaScript對象還有一個更加簡單的方法， 一行代碼即可，比如：
var cloned = JSON.parse(JSON.stringify(objectToClone));
原文地址： stackoverflow.com
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來自：http://ourjs.com/detail/55c061d3fbd23139de9e3551
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