Array of arrays contains array javascript

Question

this might be a duplicate but I couldn't find a solution. If I have an array of arrays, is there a "built-in" way to determine if that array of arrays includes another array. Array.prototype.includes() helps, but doesn't get me all the way because of (I think) object references as shown below. I can manually test equality of each value but I'm sure there's a better way.

$ node
> b = [[1,2,3]]
[ [ 1, 2, 3 ] ]
> b[0]
[ 1, 2, 3 ]
> b.includes(b[0])
true
> b.includes([1,2,3])
false
>

Note that in JavaScript `[1,2,3] !== [1,2,3]`. They are different arrays. — trincot, Dec 28 '19 at 15:38
Well the answer is there already but I would use .toString() instead — Saurav, Dec 28 '19 at 15:41
`.toString()` would not work really with nested array (e.g. `[1,2,[3,4]].toString() == [[1],2,[3],[[4]]].toString()`. Or when the array contains `,` (`[1,'2,3'].toString()==[1,2,3].toString()`) — apple apple, Dec 28 '19 at 15:52

score 3 · Accepted Answer · answered Dec 28 '19 at 15:36

3

I recommend to use JSON.stringify & includes.

JSON.stringify([[1,2,3]]).includes(JSON.stringify([1,2,3]))
true
JSON.stringify([[1,3]]).includes(JSON.stringify([1,2,3]))
false

answered Dec 28 '19 at 15:36

seunggabi

1,699
12
12

While this may be a quick and dirty solution, this has some pitfalls. To give an example: `JSON.stringify([[_ => 0]]).includes(JSON.stringify([null]))` – ASDFGerte Dec 28 '19 at 16:00
@ASDFGerte you are right, but it's only a case where the array contains functions. It's safe to use if he can assume the array contains only numbers. – Omri Attiya Dec 28 '19 at 16:33

Array of arrays contains array javascript

1 Answers1