Less boilerplate for Redux Reducers

CreateReducer.js

function createReducer(initialState, handlers) {
  return function reducer(state = initialState, action) {
    if (handlers.hasOwnProperty(action.type)) {
      return handlers[action.type](state, action)
    }

    return state
  }
}

OrdersClean.js

import { createReducer } from '../helpers/createReducer'
import { ORDERS_LOAD } from '../constants/ActionTypes'

const initialState = {
  data: [],
  error: false,
  pending: false
}

export default createReducer(initialState, {
  [ORDERS_LOAD + '_PENDING']: () => ({
    ...initialState,
    pending: true
  }),
  [ORDERS_LOAD + '_SUCCESS']: (state, { payload }) => ({
    pending: false,
    data: payload
  }),
  [ORDERS_LOAD + '_ERROR']: (state, { error }) => ({
    pending: false,
    error
  })
})

OrdersDefault.js

import { ORDERS_LOAD } from '../constants/ActionTypes'

const initialState = {
  data: [],
  error: false,
  pending: false
}

export default function ordersReducer (state = initialState, action) {
  switch (action.type) {
    case ORDERS_LOAD + '_PENDING':
      return {
        ...state,
        error: false,
        pending: true
      }
    case ORDER_LOAD + '_ERROR':
      return {
        ...state,
        error: action.error,
        pending: false
      }
    case ORDERS_LOAD + '_SUCCESS':
      return {
        ...state,
        data: action.payload,
        pending: false
      }
    default:
      return state
  }
}