text: import { RECEIVE_TWEETS, TOGGLE_TWEET, ADD_TWEET } from '../actions/tweets'
  
  export default function tweets(state = {}, action) {
      switch (action.type) {
          case RECEIVE_TWEETS:
              return {
                  ...state,
                  ...action.tweets
              }
  
          case TOGGLE_TWEET:
              return {
                  ...state,
                  [action.id]: {
                      ...state[action.id],
                      likes: action.hasLiked === true
                          ? state[action.id].likes.filter((uid) => uid !== action.authedUser)
                          : state[action.id].likes.concat([action.authedUser])
                  }
              }
          case ADD_TWEET:
              const { tweet } = action
              let replyingTo = {}
              if (tweet.replyingTo !== null) {
                  replyingTo = {
                      [tweet.replyingTo]: {
                          ...state[tweet.replyingTo],
                          replies: state[tweet.replyingTo].replies.concat([tweet.id])
                      }
                  }
              }
              return {
                  ...state,
                  [action.tweet.id]: action.tweet,
                  ...replyingTo,
              }
          default:
              return state
      }
  }