json back reference

Question

I've a hierarchical json object, I want to traverse it and attach a parent node to each element. This is what I've done

function attach_back_reference(hierarchy, parent){
    hierarchy.parent = parent;
    for(var i in hierarchy){
        if(jQuery.isPlainObject(hierarchy[i]))
            attach_back_reference(hierarchy[i], hierarchy);
    }
}

But this is giving error. Maximum call stack size exceeded

score 1 · Accepted Answer · edited May 23 '17 at 12:04

1

Since you do

for(var i in hierarchy){

after adding the parent property, one value of i will be "parent", so you end up setting the child as its own grandparent infinitely.

You can see this in

var o = {};
o.x = o;
for (var i in o) { alert(i); }

which alerts "x".

Move the loop to the top.

function attach_back_reference(hierarchy, parent){
    for(var i in hierarchy){
        if(jQuery.isPlainObject(hierarchy[i]))
            attach_back_reference(hierarchy[i], hierarchy);
    }
    hierarchy.parent = parent;
}

Alternatively, if you only need this to work on newer interpreters, you can try making the parent property unenumerable : javascript defineProperty to make an attribute non enumerable

edited May 23 '17 at 12:04

Community

1
1

answered Dec 24 '12 at 19:24

Mike Samuel

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Thanks. I overlooked that. also I found that It doesn't work if I've an array in the middle of hierarchy – Dipro Sen Dec 24 '12 at 19:26
also can you tell me how to handle arrays ? so that it assigns parent to first object(non-array) ancestor ? – Dipro Sen Dec 24 '12 at 19:29

score 0 · Answer 2 · answered Dec 24 '12 at 19:21

0

You have an infinite loop there.

You are setting the parent of each object as itself.

answered Dec 24 '12 at 19:21

Naftali

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But I am passing `attach_back_reference(hierarchy[i], hierarchy)` so `hierarchy[i].parent = hierarchy` will be executed – Dipro Sen Dec 24 '12 at 19:22

json back reference

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