Simplified reduce-reducers version, without any extra arguments supported

reduce-reducers.js

const rootReducer = (...reducers) => {
    return (stateInit, action) => {
        return reducers.reduce(
            (state, reducer, at) => {
                return reducer(state, action) || state
            },
            stateInit
        );
    }
};

// works like this
//... somewhere at React Redux initiation
const rootStorage = createStore(rootReducer(...[
  reduceFunctionOne,
  reduceFunctionTwo// ,...
]));