JavaScript check if object is array with specific values

Asked Aug 23 '18 at 11:41

Active Aug 24 '18 at 19:37

Viewed 49 times

I want to check an object which is always an array. One important case is where it is an array equivalent to foo below. But it could contain any number of integers. I need to evaluate the specific case in an if statement. However, I find the behavior confusing:

let foo = [0]

foo === [0] // false
foo == [0] // false
foo === 0 // false
foo == 0 // true

How can I check whether foo is the exact array of [0]?

Thanks!

Edit: Thanks for your comments. Not sure if this really is a duplicate. In any case, thanks for the solutions. I went for if (foo instanceof Array && foo.length == 1 && foo[0] === 0).

edited Aug 24 '18 at 19:37

asked Aug 23 '18 at 11:41

citivin

2

`if (foo instanceof Array && foo.length == 1 && foo[0] === 0)` – DontVoteMeDown Aug 23 '18 at 11:43
1

@DontVoteMeDown would also return true for `[0,1]`. – Jared Smith Aug 23 '18 at 11:45
2

@JaredSmith in that case the `length` would be `2`. – DontVoteMeDown Aug 23 '18 at 11:48
`JSON.stringify(foo) === JSON.stringify(bar)` or `foo.filter((el, index) => el === bar[index]).length === foo.length` – dziraf Aug 23 '18 at 11:50
@DontVoteMeDown that's what I get for looking at stuff on my phone. Sorry! – Jared Smith Aug 23 '18 at 13:41
@JaredSmith hahaha no problem!! – DontVoteMeDown Aug 23 '18 at 18:34

JavaScript check if object is array with specific values

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