How would I typecheck a table as an argument within a callback?

[Bettleeeeeeee (Bettlee)]

I’ve searched around on the forum and I really haven’t found something specific to my question. I have this

function Attach<T...>(Parent: T, Callback: ({ T }) -> ({ T })): ({ T })
    ...
end

and this is how I want it to be used

Attach(..., function({ Animator, Animation })
    ...
end);

, but it just errors because it doesn’t expect the {

[OniiSamaUwU (UwU)]

What exactly are you trying to accomplish? Is the generic T for Parent supposed to contain {T} for both your callback and returned values?

1. You are using a variadic generic type of T... but as a regular generic type. It’s used for, well, variadic values.

2. I find it confusing why you are using both a generic and a table for your callback. All {T} is going to return is an array only containing whatever you pass as the Parent argument.

3. Can you explain to me how this function is supposed to work.

[Bettleeeeeeee (Bettlee)]

I’m trying to share values from other places. This is what is inside of the function

local Animator: Animator, Animation: Animation;

do
	for _, Descendant: any in Parent:GetDescendants() do
		if Descendant:IsA("Animator") then

			Animator = Descendant;
		elseif Descendant:IsA("Animation") then

			Animation = Descendant;
		end
	end
end

return Callback(Animator, Animation);

[Bettleeeeeeee (Bettlee)]

I managed to figure out what to do:

return {
	
	Attach = function<P, C...>(self: {}, Parent: P, Children: { string }, Callback: (C...) -> (C...)): (C...)
	
		local Descendants: { string } = {};
		for _, Descendant: any in Parent:GetDescendants() do
			for i = 1, #Children do
				if Descendant:IsA(Children[i]) then
					
					table.insert(Descendants, Descendant);
				end
			end
		end
		return Callback(table.unpack(Descendants));
	end
}