how to check if an element exists in a javascript object [duplicate]

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.

jsfiddle: https://jsfiddle.net/3jo7vx4p/

Any help is sincerely appreciated.

hasOwnProperty - developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — Adam Jenkins
– Adam Jenkins, Commented Jun 2, 2016 at 12:21
or rather "x" in t. But it's a duplicate and a frequent question. — Denys Séguret
– Denys Séguret, Commented Jun 2, 2016 at 12:21

Adam Jenkins · Accepted Answer · 2016-06-02 12:21:50Z

2

The method your are looking for is:

hasOwnProperty

e.g:

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

}

answered Jun 2, 2016 at 12:21

Adam Jenkins

56.3k13 gold badges85 silver badges113 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

David Thomas Over a year ago

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...) :)

Jose Hermosilla Rodrigo Over a year ago

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.

Arnab Over a year ago

I need x and y to have proper values , they can not be null or undefined

Adam Jenkins Over a year ago

@Arnab - sounds like you'll need Number.isNaN - developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…. if(Number.isNaN(t.x) || Number.isNaN(t.y)) { throw new Error(...) }

Arnab Over a year ago

@Adam thanx but y is string, is there something for string which will handle null and undefined

Collectives™ on Stack Overflow

how to check if an element exists in a javascript object [duplicate]

1 Answer 1

5 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Linked

Related