Basic Redux setup with store, actionCreator & reducer that adds to immutable array

React and Redux: Extract State Logic to Redux

// define ADD, addMessage(), messageReducer(), and store here:
const ADD = 'ADD';

const messageReducer = (state = [], action) => {
  switch(action.type) {
    case ADD:
      return [
          ...state,
          action.message
      ]
    default:
      return state;
  }
};

const addMessage = (message) => {
  return {
    type: ADD,
    message: message
  };
};

const store = Redux.createStore(messageReducer);