A reducer-generator which builds a reducer that reduces an array of
reducers.
yarn add reducer-generator-array-map
or
npm install --save reducer-generator-array-map
import createArrayMapReducer from 'reducer-generator-array-map'
const system = createArrayMapReducer({ /* initial state */ }, [
  (state, action) => action.type === 'SYSTEM_ONLINE'
    ? { ...state, isOnline: true }
    : state,
  (state, action) => action.type === 'SYSTEM_OFFLINE'
    ? { ...state, isOnline: false
    : state
], /* You may pass extra args that will be passed to the reducer(s) */)