Typings

use-reducer-with-side-effects.d.ts

// Type definitions for use-reducer-with-side-effects 0.4
// Project: https://github.com/baz/foo (Does not have to be to GitHub, but prefer linking to a source code repository rather than to a project website.)
// Definitions by: Chris Dhanaraj <https://github.com/chrisdhanaraj>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped

/*~ If this module has methods, declare them as functions like so.
 */

type SideEffectArguments = {
    state: any;
    dispatch: (action: object) => void;
};

type SideEffectReturn = void | (() => void);
type SideEffectCallback = (state: any, dispatch: SideEffectArguments) => void;
type Reducer<S, A> = (prevState: S, action: A) => S;
type ReducerState<R extends Reducer<any, any>> = R extends Reducer<infer S, any> ? S : never;
type ReducerAction<R extends Reducer<any, any>> = R extends Reducer<any, infer A> ? A : never;
type Dispatch<A> = (value: A) => void;

export function UpdateWithSideEffect(newState: any, newSideEffect: SideEffectCallback): SideEffectReturn;
export function NoUpdate(): Symbol;
export function SideEffect(newSideEffect: SideEffectCallback): void;

export function useReducerWithSideEffects<R extends Reducer<any, any>, I>(
    reducer: R,
    initializerArg: I & ReducerState<R>,
    initializer: (arg: I & ReducerState<R>) => ReducerState<R>
): [ReducerState<R>, Dispatch<ReducerAction<R>>];

export function useReducer<R extends Reducer<any, any>, I>(
    reducer: R,
    initializerArg: I,
    initializer: (arg: I) => ReducerState<R>
): [ReducerState<R>, Dispatch<ReducerAction<R>>];

export function useReducer<R extends Reducer<any, any>>(
    reducer: R,
    initialState: ReducerState<R>,
    initializer?: undefined
): [ReducerState<R>, Dispatch<ReducerAction<R>>];