How to efficiently detect the existence of any keys of an object in JavaScript?

Question

What's the fastest way of detecting the existence of one or more keys inside an object? Is it possible to do it without iterating over the object by using Object.keys().length?
_{This question is almost identical to How to efficiently count the number of keys/properties of an object in JavaScript?}

Are you talking about own properties? Inherited properties? Only enumerable properties? — cookie monster
– cookie monster, Commented Jan 10, 2014 at 4:01
Yes, you said it yourself...read more here: stackoverflow.com/questions/126100/… — NewInTheBusiness
– NewInTheBusiness, Commented Jan 10, 2014 at 4:07
@cookiemonster I'm primarily want to know if the object has any properties in general. — RienNeVaPlu͢s
– RienNeVaPlu͢s, Commented Jan 10, 2014 at 4:11
Very closely related: “Falsy or empty” in JavaScript: How to treat {} and [] as false — Qantas 94 Heavy
– Qantas 94 Heavy, Commented Jan 10, 2014 at 4:33

p.s.w.g · Accepted Answer · 2014-01-10 04:07:24Z

3

Perhaps use this:

function hasProperties (obj) {
    for(var x in obj) 
        return true; 
    return false;
}

Yes, admittedly you do have to iterate over the object, but you stop after the first property is found.

answered Jan 10, 2014 at 4:07

p.s.w.g

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2 Comments

This is almost exactly how jQuery does it for its isEmptyObject() function

Note if you want it to act the same as Object.keys, you'll have to include a hasOwnProperty check.