How to type a multidimensional array whose each array has different type?

Question

For a multidimensional array whose every element has the same type, it's simple to declare: string[][].

However if each array is different, then how should I do?

function create3DArray(arg): // <----???
{ firstArray: string[] = [] 
  secondArray: number[] = [] 
  thirdArray: CustomType[] = [] 
  return [firstArray, secondArray, thirdArray] 
}

I have looked at typescript multidimensional array with different types but I'm still not sure how to do it.

score 1 · Accepted Answer · answered Jul 27 '23 at 08:45

1

You are looking for a tuple. Tuple is an array with finite length, in your case, it is three:

function create2DArray(arg):[string[], number[], CustomType[]] {}

answered Jul 27 '23 at 08:45

wonderflame

6,759
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thanks. If I want to shorten it, i.e. `function create3DArray(arg): MArray {}`, should I use type or interface for it? It seems that interface is only usable for objects, right? – Ooker Jul 27 '23 at 08:47
Yeah, just go simply with the type – wonderflame Jul 27 '23 at 08:49
why is interface only usable with objects but type can work with any, ugh, type? – Ooker Jul 27 '23 at 08:53
1

you can, but it will still require a `type`: `type MyArrBase = [string[], number[], boolean[]]` `interface MyArray extends MyArrBase {}` – wonderflame Jul 27 '23 at 08:55
I mean, why doesn't interface support array at the start? – Ooker Jul 28 '23 at 05:13
I think it is a design limitation. – wonderflame Jul 28 '23 at 07:26

How to type a multidimensional array whose each array has different type?

1 Answers1