Recursively remove object which contains empty array in nest json object

Question

I want to dynamically delete json object which contains empty array. I've found this link similar question here. But it doesn't work for me in my case.

Suppose I have a JSON object:

{"op":"1","parameters":[{"op":"2-1","parameters":[]},{"op":"2-2","parameters":[1,2]}]}

I've wrote a sample code to do the stuff recursively:

function removeEmptyArray(cJSON){
    if(!cJSON)
        return cJSON;

    for(var i=cJSON.parameters.length-1;i>=0;i--){
        if(!(cJSON.parameters[i].parameters instanceof Array))
            continue;
        if(cJSON.parameters[i].parameters.length==0){
            cJSON.parameters.splice(i,1);
        }else{
            cJSON.parameters[i] = removeEmptyArray(cJSON.parameters[i]);
        }
    }
    return cJSON;

}

the expect result is {"op":"1","parameters":[{"op":"2-2","parameters":[1,2]}]}, the code works fine.

but when I have this obj:

{"op":"1","parameters":[{"op":"2-1","parameters":[{"op":"3-1","parameters":[]}]},{"op":"2-2","parameters":[1,2,3]}]}

The output is {"op":"1","parameters":[{"op":"2-1","parameters":[]},{"op":"2-2","parameters":[1,2,3]}]}

Obviously it does not dynamically remove the json obj whose "op" is "2-1".

So how to solve it in an elegant way, using pure javascript?

what is the possible depth of your structure? is it indefinite? Are you trying to implement tree-like structure — Rouz
– Rouz, Commented Jul 12, 2016 at 8:16
@Sunson So can there be elements on the same level? If you remove one node, what should happen with children nodes? — Rouz
– Rouz, Commented Jul 12, 2016 at 8:26
@Rouz If I remove one node, only because it has no children nodes, that is, the array is empty. The example is already given in the question — Sunson
– Sunson, Commented Jul 12, 2016 at 8:31

Nina Scholz · Accepted Answer · 2016-07-12 08:50:14Z

3

You could use a breadth first algoritm, which look first in the depth and then deletes, if necessary.

function isNotEmpty(object) {
    if (Array.isArray(object.parameters)) {
        object.parameters = object.parameters.filter(isNotEmpty);
        return object.parameters.length;
    }
    return true;
}

var object = { "op": "1", "parameters": [{ "op": "2-1", "parameters": [{ "op": "3-1", "parameters": [] }] }, { "op": "2-2", "parameters": [1, 2, 3] }] };

isNotEmpty(object);
console.log(object);

answered Jul 12, 2016 at 8:50

Nina Scholz

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