What is the most efficient way to clone an object?
I've seen obj = eval(uneval(o)); being used, but that's currently Firefox-only. In Mootools 1.2, I've done things like obj = BUTS.decode(BUTS.encode(o)); but question the efficiency.
I've also seen recursive copying functions with various flaws. I'm surprised no canonical solution exists.
Javascript
- asked 9 years ago
- B Butts
2Answer
I want to note that the .clone() method in jQuery only clones DOM elements. In order to clone JavaScript objects, you would do:
// Shallow copy
var newObject = jQuery.extend({}, oldObject);
// Deep copy
var newObject = jQuery.extend(true, {}, oldObject);
More information can be found in the jQuery documentation.
I also want to note that the deep copy is actually much smarter than what is shown above – it's able to avoid many traps (trying to deep extend a DOM element, for example). It's used frequently in jQuery core and in plugins to great effect.
- answered 8 years ago
- Sandy Hook
There doesn't seem to be an in-built one, you could try:
function clone(obj) {
if(obj === null || typeof(obj) !== 'object' || 'isActiveClone' in obj)
return obj;
var temp = obj.constructor(); // changed
for(var key in obj) {
if(Object.prototype.hasOwnProperty.call(obj, key)) {
obj['isActiveClone'] = null;
temp[key] = clone(obj[key]);
delete obj['isActiveClone'];
}
}
return temp;
}
- answered 8 years ago
- G John
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