How can I tell if an object is empty?

Question

I hope this makes sense. If I have an object:

 var a = {"minlength":true}
 var a = {}

How can I tell if the object is empty (the second line of code)

http://stackoverflow.com/questions/679915/how-do-i-test-for-an-empty-javascript-object — pbaldauf, Apr 14 '15 at 16:58

score 5 · Accepted Answer · answered Apr 14 '15 at 16:57

5

Object.keys(a).length === 0

should do the trick.

answered Apr 14 '15 at 16:57

score 0 · Answer 2 · answered Apr 14 '15 at 16:58

0

You should check for undefined as well:

if (a != undefined) {
    // object is defined, you can do stuff now
}

answered Apr 14 '15 at 16:58

Code Whisperer

score 0 · Answer 3 · edited Apr 14 '15 at 17:01

0

Object.keys(a) returns a list of keys, so Object.keys(a).length == 0 means it's empty.

edited Apr 14 '15 at 17:01

Undo

answered Apr 14 '15 at 16:59

Tianxiang Zhang

3 Answers3