How to validate that something is an array, not caring about the items in the array(performance)

[itsramiel]

Hi,

I would like to validate that something is an array without validating the items inside the array. Simple knowing that it is an array is enough for me. The return type could be: Array<unknown>, how can I do that?

I see that array always loops through its item, but for performance reasons I dont care to validate the items:

valibot/library/src/schemas/array/array.ts

Lines 91 to 98 in d7ef5fb

	if (Array.isArray(input)) {
	// Set typed to `true` and value to empty array
	dataset.typed = true;
	dataset.value = [];
	// Parse schema of each array item
	for (let key = 0; key < input.length; key++) {
	const value = input[key];

[itsramiel]

Like this maybe:

v.custom<Array<unknown>>((x) => Array.isArray(x))

or is there a better way?

[fabian-hiller]

Yes, this is the fastest approach. You could also write v.array(v.unknown()) but its much slower compared.

[itsramiel]

Is there a use case os v.array(v.unknown)? Why cant v.array accept no arguments and then there would be no validation for the items and the type would be Array<unknown>?

It doesnt make sense to me to loop over the array and check the unknown schema since there is no such javascript concept in the beginning. What do you think of the suggestion above? Does it work well with other parts of the schemas?

[fabian-hiller]

Great idea! But on the other hand I think this is a very rare case and in most situations performance doesn't really matter here. If more people request this behavior, I will think about it.