Change JSON key names (to all capitalized) recursively?

Question

Is there a way to change all JSON key names to capital letter ?

eg:

{"name":"john","Age":"21","sex":"male","place":{"state":"ca"}}

and need to be converted as

{"NAME":"john","AGE":"21","SEX":"male","PLACE":{"STATE":"ca"}}

Selvakumar Arumugam · Accepted Answer · 2012-04-17T18:41:19.830

17

From your comment,

eg like these will fail for the inner keys {"name":"john","Age":"21","sex":"male","place":{"state":"ca"}}

You may need to use recursion for such cases. See below,

DEMO

var output = allKeysToUpperCase(obj);

function allKeysToUpperCase(obj) {
    var output = {};
    for (i in obj) {
        if (Object.prototype.toString.apply(obj[i]) === '[object Object]') {
            output[i.toUpperCase()] = allKeysToUpperCase(obj[i]);
        } else {
            output[i.toUpperCase()] = obj[i];
        }
    }
    return output;
}

Output

enter image description here

A simple loop should do the trick,

DEMO

var output = {};
for (i in obj) {
   output[i.toUpperCase()] = obj[i];
}

edited Apr 17 '12 at 18:41

answered Apr 17 '12 at 18:20

Selvakumar Arumugam

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Do note that the keys in lowercase are still present – Elvis D'Souza Apr 17 '12 at 18:22
2

@Elvis Nope, I am creating a new object `output` – Selvakumar Arumugam Apr 17 '12 at 18:23
eg like these will fail for the inner keys `{"name":"john","Age":"21","sex":"male","place":{"state":"ca"}}` – Navin Leon Apr 17 '12 at 18:26
@NavinLeon What do you mean by inner keys? Can you explain more on why it would fail? – Selvakumar Arumugam Apr 17 '12 at 18:28
@Vega sorry I pasted the wrong code earlier, now I edited above. The key "state" is still in small letter. – Navin Leon Apr 17 '12 at 18:30
@NavinLeon Please update your question with the updated key. The above answer is for a simple structure with {key : value} pair where value is a simple string. – Selvakumar Arumugam Apr 17 '12 at 18:32
@Vega I have updated the question, the "state" key is still in small letter if I follow your code. The code is not converting inner objects but outer objects are working perfectly fine. – Navin Leon Apr 17 '12 at 18:38
1

@NavinLeon See my updated code which uses recursion to loop thru inner objects. Try and let me know. – Selvakumar Arumugam Apr 17 '12 at 18:41
Curious about the condition in the if() condition. Couldn't you just say if(typeof d === 'object') ? – Nov 21 '14 at 20:31
Here is a version that looks in arrays and keeps them arrays. (@nnyby 's version turns them in objects) My version is for converting first letters of keys to lowercase as "MyKey" to "myKey". https://pastebin.com/G7feBj3C – Fanky Aug 10 '17 at 17:49
what if i wanted to uppercase everything else too? – aero Nov 03 '17 at 22:18

jfriend00 · Answer 2 · 2016-08-26T16:51:34.160

You can't change a key directly on a given object, but if you want to make this change on the original object, you can save the new uppercase key and remove the old one:

function changeKeysToUpper(obj) {
    var key, upKey;
    for (key in obj) {
        if (obj.hasOwnProperty(key)) {
            upKey = key.toUpperCase();
            if (upKey !== key) {
                obj[upKey] = obj[key];
                delete(obj[key]);
            }
            // recurse
            if (typeof obj[upKey] === "object") {
                changeKeysToUpper(obj[upKey]);
            }
        }
    }
    return obj;
}

var test = {"name": "john", "Age": "21", "sex": "male", "place": {"state": "ca"}, "family": [{child: "bob"}, {child: "jack"}]};

console.log(changeKeysToUpper(test));

FYI, this function also protects again inadvertently modifying inherited enumerable properties or methods.

Added code to work recursively and added working snippet demo. — jfriend00, Aug 26 '16 at 16:49

Change JSON key names (to all capitalized) recursively?

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