Array of arrays contains array javascript [duplicate]

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
– trincot, Commented Dec 28, 2019 at 15:38
Well the answer is there already but I would use .toString() instead — Saurav
– Saurav, Commented Dec 28, 2019 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
– apple apple, Commented Dec 28, 2019 at 15:52

seunggabi · Accepted Answer · 2019-12-28 15:36:44Z

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, 2019 at 15:36

seunggabi

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2 Comments

ASDFGerte Over a year ago

While this may be a quick and dirty solution, this has some pitfalls. To give an example: JSON.stringify([[_ => 0]]).includes(JSON.stringify([null]))

Omri Attiya Over a year ago

@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.

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