How to check if an object is empty? [javascript]

Question

I need to evaluate if an object is empty.

For example suppose I have an object:

var home = ....;     // this is an object and after I print it

console.log(home)    // the result of this option is []

//now I need to check if a object is empty or null
if( home == null || home == undefined )
{
    // I don't know specify how object is empty
}

How can I detect whether or not the above object home is null/empty?

if I try home.length gives me an error "length is undefined" — user6045391, Mar 10 '16 at 14:48
@user6045391, add the code for `home` to your question. `home.length` should work unless you're actually using a JS object (not an array) which needs an alternative method to check whether it's empty. — Andy, Mar 10 '16 at 14:49
@Andy I do home.length and I obtain "Cannot read property 'length' of undefined"... I print console(typeof home) and I get object what I must do? — user6045391, Mar 10 '16 at 14:58
Add `home` to your question. Is it `var home = []` or `var home = {}`? — Andy, Mar 10 '16 at 14:59
cf. http://stackoverflow.com/questions/154059/how-do-you-check-for-an-empty-string-in-javascript — J Burnett, Mar 10 '16 at 15:17

score 2 · Answer 1 · answered Mar 10 '16 at 14:57

2

To check for an empty array

if (!arr.length) {
  // if the array is empty
}

and for an object (check that it has no keys)

if (!Object.keys(obj).length) {
  // if the object is empty
}

DEMO

answered Mar 10 '16 at 14:57

Andy

61,948
13
68
95

I use all two method and I have the same error, but the vector that I use it is result from var vet = $(this).find('...').map(function() { return { 'name': this.id, 'value': this.value }; }).get(); – user6045391 Mar 10 '16 at 15:26
when the fields are the value the problem doesn't exist,but when I leave the fields empty I have this problem! – user6045391 Mar 10 '16 at 15:27
At the risk of repeating myself, add the relevant code/HTML to your question. You're now asking about jQuery which doesn't get a mention in your question. If you don't give us all the information, how can we help you? – Andy Mar 10 '16 at 15:31

score 0 · Answer 2 · answered Mar 10 '16 at 15:00

0

Only way I see so far may be ({}).toSource() === o.toSource()

Example:

var y = {a: 't'};
window.console.log(({}).toSource() === y.toSource());
delete y.a;
window.console.log(({}).toSource() === y.toSource());

EDIT : Oh, nicely found, Andy.

answered Mar 10 '16 at 15:00

capqch

46
2

How to check if an object is empty? [javascript]

2 Answers2