Remove element from JSON Object

Question

I have a json array which looks something like this:

  {
    "id": 1,
    "children": [
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    },
    {
        "id": 2,
        "children": {
            "id": 3,
            "children": {
                "id": 4,
                "children": ""
            }
        }
    }]
}

I would like to have a function which removes the elements which has the "children" empty. How can I do it? I am not asking for the answer, only suggestions

@magritte stop with this redundant question. he said he is asking for suggestions. not the answer/ — Royi Namir, Mar 16 '13 at 15:57
i know that is not a valid json ... i just wanted to give an example of how it looks. — Stack Overfolow, Mar 16 '13 at 16:01
@StackOverfolow dont worry. you are allowed to be wrong. this is why we are here.I made your JSON into a valid one. continue from here. — Royi Namir, Mar 16 '13 at 16:05
@StackOverfolow Can you show some less-vague data? There are multiple "children" keys here at different levels. What `children` are you pointing to? — Lekensteyn, Mar 16 '13 at 16:13
If you say you've got an array, please post an array. And check out the [`filter` array function](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/filter) — Bergi, Mar 16 '13 at 16:19

Lekensteyn · Accepted Answer · 2013-03-16T16:12:02.630

71

To iterate through the keys of an object, use a for .. in loop:

for (var key in json_obj) {
    if (json_obj.hasOwnProperty(key)) {
        // do something with `key'
    }
}

To test all elements for empty children, you can use a recursive approach: iterate through all elements and recursively test their children too.

Removing a property of an object can be done by using the delete keyword:

var someObj = {
    "one": 123,
    "two": 345
};
var key = "one";
delete someObj[key];
console.log(someObj); // prints { "two": 345 }

Documentation:

edited Mar 16 '13 at 16:12

answered Mar 16 '13 at 16:05

Lekensteyn

64,486
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11

+1 ... I've been coding in Javascript for years and I didn't even know the [delete](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/delete) operator existed?! – Emissary Mar 16 '13 at 16:07
3

I think he should use the splice() method rather than delete since the children are held in an array? – magritte Mar 16 '13 at 16:18
@magritte He has listen both arrays and objects. I'm waiting for some clarification, but yes, if there are arrays he can use `splice` to remove elements or use [`filter`](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/filter) to iterate and remove stuff. – Lekensteyn Mar 16 '13 at 16:21
3

+1 it is the place to clear out that delete wont delete an array element from array but replace it with undefined. delete is only for deleting props from object. – Royi Namir Mar 16 '13 at 16:26

score 2 · Answer 2 · answered Mar 16 '13 at 16:16

JSfiddle

function deleteEmpty(obj){
        for(var k in obj)
         if(k == "children"){
             if(obj[k]){
                     deleteEmpty(obj[k]);
             }else{
                   delete obj.children;
              } 
         }
    }

for(var i=0; i< a.children.length; i++){
 deleteEmpty(a.children[i])
}

Remove element from JSON Object

2 Answers2

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