@react-nano/tsrux/dist/mapReducers.js

tsrux stands for typesafe redux. It reduces boilerplate redux code.

/**
 * Creates a reducer, which is capable of infering the type of action for each reducer based on the action-creators.
 *
 * @param defaultState  The initial state value
 * @param setup         This function is used to set up the contained reducers.
 */
export function mapReducers(defaultState, setup) {
    const map = Object.assign({}, ...setup((actionCreator, reducer) => ({ [actionCreator.type]: reducer })));
    // eslint-disable-next-line default-param-last, @typescript-eslint/default-param-last
    return (state = defaultState, action) => {
        const reducer = map[action.type];
        return reducer ? reducer(state, action) : state;
    };
}