How to create a type of array values?

Question

I want to create a type that only accepts a specific combination of array values regardless of their order.

For example:

const acceptedCombo = ['a', 'b'];

function foo(param: MyType) {}

// Possible combos:
['a', 'b'] // OK
['b', 'a'] // OK
['a', 'b', 'c'] // TypeError - "c" is extra
['a'] // TypeError - "b" is missing

How can I define MyType?

[this](https://stackoverflow.com/questions/69676439/create-constant-array-type-from-an-object-type/69676731#69676731) answer is related, however it also allows less elements — captain-yossarian from Ukraine, Nov 30 '22 at 10:43
There is also this: https://tsplay.dev/WYRv2w. It checks if all elements are present, although doubled elements are allowed. Has the advantage of not being combinatory explosive. — Tobias S., Nov 30 '22 at 10:49

score 0 · Answer 1 · answered Nov 30 '22 at 10:45

0

You can do it by this way:

type MyType = [string, string];

answered Nov 30 '22 at 10:45

Usitha Indeewara

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this doesn't restrict the string to being 'a' and 'b' it could literally be anything. captain-yossarian from Ukraine answer in the comments should be sufficient. – Derek Lawrence Nov 30 '22 at 16:38

How to create a type of array values?

1 Answers1