Why is a generic needed for the selectionMode in the Select component?

[DarkstarXDD]

Hey, what's the reason behind we needing to pass a generic for the selectionMode prop in the Select component?

Currently, Select prop types needs to look like this. Without the generic passed in, only "single" will be the option.

function Select<
  T extends object, 
  M extends "multiple" | "single" = "single"
>({...props}: SelectProps<T, M>)

But for example, selectionMode for ListBox is typed like this: type SelectionMode = 'none' | 'single' | 'multiple';.

So we don't need to pass a generic.

function ListBox<T extends object>({
  ...props
}: ListBoxProps<T>) {

But for some reason for the Select we need it. Why is that? Can't it be typed within the library code so it works like the ListBox so we don't need to pass the generic when consuming the component?

[devongovett]

The type of the value prop changes to an array when multiple selection is enabled.

[DarkstarXDD]

Ah got it. Looks like it's this:

react-spectrum/packages/@react-types/select/src/index.d.ts

Lines 35 to 36 in ca871ae

	export type ValueType<M extends SelectionMode> = M extends 'single' ? Key | null : readonly Key[];
	export type ChangeValueType<M extends SelectionMode> = M extends 'single' ? Key | null : Key[];

Thank you for the response!