Hook functions require a void return type

[chrbala]

I'm not sure if this should be filed under bug or feature request.

Basically the hooks have a void return type, which means that you can't return any value, whether the return value is used or not.

type OnDragStartHook = (start: DragStart, provided: HookProvided) => void;
type OnDragUpdateHook = (update: DragUpdate, provided: HookProvided) => void;
type OnDragEndHook = (result: DropResult, provided: HookProvided) => void;

This means that we can't do:

<DragDropContext onDragStart={someFunctionThatReturnsValue} />

Instead, we have to proxy the function like this:

<DragDropContext onDragStart={(...args) => { someFunctionThatReturnsValue(...args) }} />

Since the return isn't used anyway, is there a reason why these aren't typed with a mixed return type? This is how I typically type event handlers in order to give more freedom.

[alexreardon]

If we change the return type to mixed it might imply that we are doing something with the return value, which we are not. I think this could be a source of confusion for people

[chrbala]

This is what the flow docs recommend for cases like this. I think people familiar with flow will understand that the return value may not actually be used. If you're still concerned, you could explain why the return type is mixed by the type definition.

[alexreardon]

Fair enough! Happy to update the types. I think it would be also worth calling out in the docs that we do not use the return type

[alexreardon]

I think this would be a good candidate for a first contribution 😊

[alexreardon]

This will ship in our next release! Thanks @kylehalleman!!