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Javascript object deep copy
function processObjWithRef(obj, result){
if(obj==null || typeof obj != 'object'){
//nothing really to do here - you're going to lose the reference to result if you try an assignment
if(obj instanceof Array) {
for(var i=0; i<obj.length; i++){
processObjWithRef(obj[i], result[i]);
if(obj instanceof Object){
for(var k in obj){
var count=0;
if(obj[k]==null || typeof obj[k] != 'object'){
result[k] = obj[k];
}else if(obj[k] instanceof Array) {
result[k] = [];
processObjWithRef(obj[k], result[k]);
}else if(obj[k] instanceof Object){
result[k] = {};
for( var attr in obj[k]){
processObjWithRef(obj[k], result[k]);

What is line 13 suppose to be counting?


Probably our ability to detect a leftover variable. 😄 Should be using Array.isArray() to detect arrays, probably, and using "===" for comparison against null. The last loop would be a lot faster using function variables rather than if() tests, but one would have to use typeof instead of instanceof in order to make that work.


This fails while cloning a simple case: var b = { a: 10, b: { ba: new Date(), bb: [ 1, 2, { bba: 'pp' } ] } }; var c = {}; processObjWithRef( b, c );. Fails with TypeError: Cannot set property 'bba' of undefined

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