Accept generics in hook

[yuritoledo]

Hey!

Actually I am using const list = useList()

function useListContext() {
  const [data, setData] = useState([])

 
  // ommited

  return {
    data,
    feedData,
  }
}

export const [
  ListProvider,
  useList, // I want to pass the generics to this hook, to use in setData state
] = constate(useListContext)

There are any support like these in your roadmap?

Thanks

[diegohaz]

I don't understand what you mean. Could you elaborate?

[yuritoledo]

Sure, is something like this:

// page_component.ts

type TOrders = {
  foo: string,
  bar: boolean
}

const list = useList<TOrders[]>()

typeof list.data === TOrders[]

// hook_component.ts

function useListContext<T>() {
  const [data, setData] = useState(T[])

 
  // ommited

  return {
    data,
    feedData,
  }
}

export const [
  ListProvider,
  useList,
] = constate(useListContext)

Today, constate doesn't accept this.

Is it better now?

[diegohaz]

Got it! Thanks!

I don't know if that's possible. But if you know how to implement that, I would accept a PR.

Right now, the only solution I can think of is casting the function in your app:

const [ListProvider, _useList] = constate(useListContext);

export const useList = _useList as <T>() => T[];

[yuritoledo]

Great, I will check how this cast implementation works here.

And I will try to find some way to open a PR, i really like this lib.

Thank you for your attention!

[caasi]

Is this possible by change these:

function createUseContext(context: React.Context<any>): any {
  return () => {
    const value = React.useContext(context);
    if (isDev && value === NO_PROVIDER) {
      // eslint-disable-next-line no-console
      console.warn("[constate] Component not wrapped within a Provider.");
    }
    return value;
  };
}

// ...

function constate<P, V, S extends Array<SplitValueFunction<V>>>(
  useValue: (props: P) => V,
  ...splitValues: S
): ContextHookReturn<P, V, S> {
  const Context = React.createContext(NO_PROVIDER as V);
  // ...
  const useContext: any = () => {
    if (isDev) {
      // eslint-disable-next-line no-console
      console.warn(
        "[constate] Using the return value of constate as a hook is deprecated. " +
          "Please, use the tuple format instead. " +
          "See instructions on https://github.com/diegohaz/constate/pull/101"
      );
    }
    return createUseContext(Context)();
  };
 // ...
}

to:

function createUseContext(context: React.Context<T>): T {
  return () => {
    const value = React.useContext(context);
    if (isDev && value === NO_PROVIDER) {
      // eslint-disable-next-line no-console
      console.warn("[constate] Component not wrapped within a Provider.");
    }
    return value;
  };
}

// ...

function constate<P, V, S extends Array<SplitValueFunction<V>>>(
  useValue: (props: P) => V,
  ...splitValues: S
): ContextHookReturn<P, V, S> {
  const Context = React.createContext(NO_PROVIDER as V); // as React.Context<V>
  // ...
  const useContext: V = () => {
    if (isDev) {
      // eslint-disable-next-line no-console
      console.warn(
        "[constate] Using the return value of constate as a hook is deprecated. " +
          "Please, use the tuple format instead. " +
          "See instructions on https://github.com/diegohaz/constate/pull/101"
      );
    }
    return createUseContext(Context)();
  };
 // ...
}

I am sorry that I am unable to create a real patch right now.

[mayteio]

Additionally, it would be great to pass generics to the Provider (current types don't like it). Here's a trivial codesandbox showing the issue.

import constate from "constate";

type UseGenericProps<G> = {
  custom: G;
};

export function useGenericExample<Generic extends string>({
  custom
}: UseGenericProps<Generic>) {
  return custom;
}

export const [GenericProvider, useGeneric] = constate(
  // TS Error 1
  useGenericExample
);

function Consumer() {
  // type is `unknown`
  const value = useGeneric();
  return <>{value}</>;
}

export default function App() {
  return (
    <GenericProvider<
      // TS error 2
      "type-argument"
    > custom="type-argument">
      <Consumer />
    </GenericProvider>
  );
}

TS Error 1;

function useGenericExample<Generic extends string>({ custom }: UseGenericProps<Generic>): Generic
Argument of type '<Generic extends string>({ custom }: UseGenericProps<Generic>) => Generic' is not assignable to parameter of type '(props: unknown) => string'.
  Types of parameters '__0' and 'props' are incompatible.
    Type 'unknown' is not assignable to type 'UseGenericProps<string>'. ts(2345)

TS Error 2;

Expected 0 type arguments, but got 1.ts(2558)

[onionhammer]

It would be great if this were supported

[jsutaria]

Also would love if this was supported.