how to check if an element exists in a javascript object

Question

I have a js object as below.

var t = { x: 0, y: 'string', v: 10000 };

my present code is.

if (!t.x || !t.y) {
    throw "x and y required";
}

My problem is in my code x can have the value 0 but if in that case I do a !t.x then I get true.

How can I ensure that my data has x and y and also ensure that x can have the value 0.

Any help is sincerely appreciated.

`hasOwnProperty` - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty — Adam Jenkins, Jun 02 '16 at 12:21
or rather `"x" in t`. But it's a duplicate and a frequent question. — Denys Séguret, Jun 02 '16 at 12:21

score 2 · Answer 1 · answered Jun 02 '16 at 12:21

2

The method your are looking for is:

e.g:

if(!t.hasOwnProperty('x') || !t.hasOwnProperty('y')) {

}

answered Jun 02 '16 at 12:21

Adam Jenkins

Or the ridiculously over-complex: `Object.keys(t).indexOf('x') === -1` (for the sake of a full answer, really, I would absolutely *not* recommend this approach ever...) :) – David Thomas Jun 02 '16 at 12:23
But the question was : How can I ensure that my data has x and y and also ensure that x can have the value 0 ? With your code x and y could be undefined and will pass the test. I would check x and y to be a number too. – Jose Hermosilla Rodrigo Jun 02 '16 at 12:28
I need x and y to have proper values , they can not be null or undefined – Arnab Jun 02 '16 at 12:38
@Arnab - sounds like you'll need `Number.isNaN` - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN. `if(Number.isNaN(t.x) || Number.isNaN(t.y)) { throw new Error(...) }` – Adam Jenkins Jun 02 '16 at 12:57
@Adam thanx but y is string, is there something for string which will handle null and undefined – Arnab Jun 02 '16 at 14:56

1 Answers1