redux genericReducer

configureStore.js

import {combineReducers, createStore} from "redux";

import todosActions from './actions/todos'

const genericReducer = (storeName, initialState = null, actions = {}) => {
  return {
    [storeName]: (state = initialState, action) => {
      if (action.type === 'HYDRATE' && action.data[storeName])
        return action.data[storeName]

      let handler = actions[action.type]
      return handler ? handler(state, action) : state
    }
  }
}

const rootReducer = combineReducers({
  ...genericReducer('users' , []),
  ...genericReducer('todos' , [], todosActions.handlers)
})

export default initialState => createStore(rootReducer, initialState)

index.js

// actions/todos/index.js

const handlers = {
  ADD_TODO(state, {todo}) {
    return [...state, todo]
  }
}

const creators = {
  addTodo(todo) {
    return {
      type: 'ADD_TODO',
      todo
    }
  }
}

export default {
  handlers,
  creators
}