get size of JSON object

Question

i have a JSON object that gets returned by an AJAX request and I am having some trouble with the .length because it keeps returning undefined. Just wondering if I'm using it right:

console.log(data.length);
console.log(data.phones.length);

They both return undefined even though they are valid objects.

Update:
Sample of the JSON object returned:

{"reqStatus":true,"phones":{"one":{"number":"XXXXXXXXXX","type":"mobile"},"two":{"number":"XXXXXXXXXX","type":"mobile"}}}

I'm not sure, wasn't me. I think your question is fine, as well. — Joe, Jul 20 '11 at 18:54
To those came here via Google: Try solutions given below but check spellings also before that. In my case I was writing `.lenght` instead of `.length` and typescript interpreter never complained. Welcome to scripting world! — Atul, Feb 08 '22 at 18:29

score 700 · Accepted Answer · edited Jun 07 '21 at 23:36

700

You can use something like this

var myObject = {'name':'Kasun', 'address':'columbo','age': '29'}

var count = Object.keys(myObject).length;
console.log(count);

edited Jun 07 '21 at 23:36

Sastrija

3,284
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answered Jan 17 '13 at 12:49

Kasun

7,161
2
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70

@Matt, It is NOT compulsory for every code to work in IE 7 or 8. These inadequate or non standard platforms being protected are simply drawbacks. – Olofu Mark Jun 11 '13 at 12:46
5

@OlofuMark not everyone gets to choose which browser they're using (e.g. locked-down networks, versioned IE DLLs dependencies used by in-house applications). If accommodating outdated browsers requires significant effort then ignoring them can be justified, but in such a trivial case as this it's just rude not to – tomfumb Sep 04 '13 at 15:36
7

@OlofuMark While it is not required to support those versions, developers should know when code they produce will not work on certain versions so that they can decide whether to take that into account or not. – David Navarre Feb 25 '14 at 18:54
it's a fantastic solution to get length of json objects – Shaymol Bapary May 05 '18 at 06:06

score 55 · Answer 2 · edited Apr 01 '19 at 20:20

Your problem is that your phones object doesn't have a length property (unless you define it somewhere in the JSON that you return) as objects aren't the same as arrays, even when used as associative arrays. If the phones object was an array it would have a length. You have two options (maybe more).

Change your JSON structure (assuming this is possible) so that 'phones' becomes
```
"phones":[{"number":"XXXXXXXXXX","type":"mobile"},{"number":"XXXXXXXXXX","type":"mobile"}]
```
(note there is no word-numbered identifier for each phone as they are returned in a 0-indexed array). In this response phones.length will be valid.

Iterate through the objects contained within your phones object and count them as you go, e.g.

var key, count = 0;
for(key in data.phones) {
  if(data.phones.hasOwnProperty(key)) {
    count++;
  }
}

If you're only targeting new browsers option 2 could look like this

How would I get the length of the of the JSON object with the first solution given that my JSON object is stored in a variable called jsonObject and I have the same JSON as above: "phones":[{"number":"XXXXXXXXXX","type":"mobile"},{"number":"XXXXXXXXXX","type":"mobile"}] — Erick, Feb 07 '16 at 18:55

score 36 · Answer 3 · answered Jan 20 '16 at 15:03

36

you dont need to change your JSON format.

replace:

console.log(data.phones.length);

with:

console.log( Object.keys( data.phones ).length ) ;

answered Jan 20 '16 at 15:03

kkk

818
8
11

score 30 · Answer 4 · answered Mar 06 '13 at 10:54

30

Consider using underscore.js. It will allow you to check the size i.e. like that:

var data = {one : 1, two : 2, three : 3};
_.size(data);
//=> 3
_.keys(data);
//=> ["one", "two", "three"]
_.keys(data).length;
//=> 3

answered Mar 06 '13 at 10:54

ForestierSimon

415
4
8

score 19 · Answer 5 · answered Mar 25 '15 at 06:53

19

var json=[{"id":"431","code":"0.85.PSFR01215","price":"2457.77","volume":"23.0","total":"565.29"},{"id":"430","code":"0.85.PSFR00608","price":"1752.45","volume":"4.0","total":"70.1"},{"id":"429","code":"0.84.SMAB00060","price":"4147.5","volume":"2.0","total":"82.95"},{"id":"428","code":"0.84.SMAB00050","price":"4077.5","volume":"3.0","total":"122.32"}] 
var obj = JSON.parse(json);
var length = Object.keys(obj).length; //you get length json result 4

answered Mar 25 '15 at 06:53

surya handoko

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This is an already parsed json object. If you execute the above statements, it will give you an error 'Unexpected token o in Json'. For calculating the length of json you can directly do var length= Object.keys(json).length. – Aayushi Jul 16 '17 at 18:03

score 5 · Answer 6 · answered Jan 14 '19 at 05:37

5

try this

$.parseJSON(data).length

answered Jan 14 '19 at 05:37

Hafsal Rh

191
1
3

Mahesh Gawhane · Answer 7 · 2021-09-23T13:29:36.950

2

use this one

Object.keys(jsonObject).length

edited Sep 23 '21 at 13:29

answered Jun 02 '16 at 09:11

Mahesh Gawhane

348
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length() is not a JSON object funtion – Sunding Wei May 11 '18 at 08:02
@SundingWei maybe you shouldn't put parentheses --- just .length instead of .length(). – ajthealchemist Jan 12 '22 at 13:29

score 0 · Answer 8 · answered May 20 '23 at 05:49

var data = {"reqStatus":true,"phones":{"one":{"number":"XXXXXXXXXX","type":"mobile"},"two":{"number":"XXXXXXXXXX","type":"mobile"}}}

console.log(Object.keys(data).length);

console.log(Object.keys(data.phones).length);

console.log(Object.keys(data.phones.two).length);

score -8 · Answer 9 · edited Sep 05 '17 at 07:14

-8

$(document).ready(function () {
    $('#count_my_data').click(function () {
        var count = 0;
        while (true) {
             try {
                var v1 = mydata[count].TechnologyId.toString();
                count = count + 1;
            }
            catch (e)
            { break; }
        }
        alert(count);
    });
});

edited Sep 05 '17 at 07:14

Komal12

3,340
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answered Aug 16 '13 at 12:39

user2674838

1
1

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waiting for an exception to tell you your list has run out of elements is a bad idea, and this approach will silently give the wrong count if any element (even the last) is missing the `TechnologyId` property – tomfumb Feb 14 '14 at 18:15
2

This code is so bad, that I am not even gonna comment further. Voted -1! – Georgi-it Nov 28 '14 at 12:19

get size of JSON object

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