To check the JavaScript object has a value

Question

Can you tell me how to check the JavaScript object has a value ? This vm.occupantDetail.contactDetail object is neither null nor undefined.It looks like as shown below at run time.

It defines as shown below.

 vm.occupantDetail = {
            contactDetail: {},
     };

Possible duplicate of [How do I check if an object has a property in JavaScript?](http://stackoverflow.com/questions/135448/how-do-i-check-if-an-object-has-a-property-in-javascript) — U r s u s, Jun 28 '16 at 10:58
Possible duplicate of [How do I test for an empty JavaScript object?](http://stackoverflow.com/questions/679915/how-do-i-test-for-an-empty-javascript-object) — James Thorpe, Jun 28 '16 at 10:59

Oxi · Accepted Answer · 2016-06-28T11:05:46.567

3

You can find the it using

Object.keys(vm.occupantDetail.contactDetail).length

edited Jun 28 '16 at 11:05

answered Jun 28 '16 at 11:02

Oxi

2,918
17
28

Can you tell me what is `a` ? Or can you show how to do that by using same object which I have used ? – Sampath Jun 28 '16 at 11:04
its the object you want check for, in your case `vm.occupantDetail.contactDetail` – Oxi Jun 28 '16 at 11:05

score 0 · Answer 2 · answered Jun 28 '16 at 11:00

0

It appears from your code that your vm.occupantDetail.contactDetail object is simply an empty object, and the __proto__ property that you are seeing is the protoype property of the Object. If you want to check if an object is null, the following conditional will do the job.

if (obj == null) { ... }

However, it appears that you want to check if an object is empty, which is different. If you want to check if a specified object has no assigned properties, try the following function.

function isEmpty(map) {
   for(var key in map) {
      if (map.hasOwnProperty(key)) {
         return false;
      }
   }
   return true;
}

answered Jun 28 '16 at 11:00

Patrick Bell

769
3
15

Wouldn't it be easier to do `Object.getOwnPropertyNames(obj).length === 0`? – domyos Jun 28 '16 at 11:04
@domyos I think that may run into issues if you extend the `Object` via prototype, I'm not 100% sure though. – Patrick Bell Jun 28 '16 at 11:06

M.Tanzil · Answer 3 · 2016-06-28T11:09:35.170

0

Check the length of your object also the length of your keys.

        if (Object.keys(vm.occupantDetail.contactDetail).length > 0)
        { 
            // vm.occupantDetail.contactDetail has values
        }

edited Jun 28 '16 at 11:09

answered Jun 28 '16 at 11:04

M.Tanzil

1,987
1
12
28

score 0 · Answer 4 · answered Jun 28 '16 at 11:04

0

check it by jQuery.isEmptyObject()

jQuery.isEmptyObject({}); // true
jQuery.isEmptyObject({ foo: "bar" });

https://api.jquery.com/jQuery.isEmptyObject/

answered Jun 28 '16 at 11:04

bhupesh

104
9

To check the JavaScript object has a value

4 Answers4