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import { MutableRefObject, useCallback, useRef, useState } from 'react';
import useUpdateEffect from '../useUpdateEffect';
type Dispatch<Action> = (action: Action) => void;
interface Store<Action, State> {
getState: () => State;
dispatch: Dispatch<Action>;
}
type Middleware<Action, State> = (
store: Store<Action, State>
) => (next: Dispatch<Action>) => (action: Action) => void;
function composeMiddleware<Action, State>(chain: Middleware<Action, State>[]) {
return (context: Store<Action, State>, dispatch: Dispatch<Action>) => {
return chain.reduceRight((res, middleware) => {
return middleware(context)(res);
}, dispatch);
};
}
const createReducer = <Action, State>(...middlewares: Middleware<Action, State>[]) => {
const composedMiddleware = composeMiddleware<Action, State>(middlewares);
return (
reducer: (state: State, action: Action) => State,
initialState: State,
initializer = (value: State) => value
): [State, Dispatch<Action>] => {
const ref = useRef(initializer(initialState));
const [, setState] = useState(ref.current);
const dispatch = useCallback(
(action) => {
ref.current = reducer(ref.current, action);
setState(ref.current);
return action;
},
[reducer]
);
const dispatchRef: MutableRefObject<Dispatch<Action>> = useRef(
composedMiddleware(
{
getState: () => ref.current,
dispatch: (...args: [Action]) => dispatchRef.current(...args),
},
dispatch
)
);
useUpdateEffect(() => {
dispatchRef.current = composedMiddleware(
{
getState: () => ref.current,
dispatch: (...args: [Action]) => dispatchRef.current(...args),
},
dispatch
);
}, [dispatch]);
return [ref.current, dispatchRef.current];
};
};
export default createReducer;
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