mini-twitter.js

class FakeTwitter {
  constructor(props) {
    this.redisDatabase = {};
  }

  addFollower(user_id, follower_id) {
    // When someone follows the user, store his/her data
    this.redisDatabase[user_id].followers.push(follower_id);
  }

  createUser(id) {
    // When you create the user,
    // create an empty container in redis to hold their timeline
    this.redisDatabase[id] = { followers: [], timeline: [], tweets: [] };
  }

  recordTweet(id, tweetText) {
    // when someone tweets, record the tweet
    this.redisDatabase[id].tweets.push(tweetText);

    // then find all his followers
    // and push the tweet into their timeline array.
    // like the way post offices send mails to your box.
    let followers = this.redisDatabase[id].followers;

    for (const follower of followers) {
      // Ideally you should be pushing id's not text
      // but this is just a demo for you to understand what's going on
      this.redisDatabase[follower].timeline.push({
        id,
        tweet: tweetText
      });
    }
  }

  retweet(retweeted_by, tweetText) {
    // when you retweet, we record the tweet
    this.recordTweet(retweeted_by, tweetText);
  }

  refreshTimeline(id) {
    // When someone refreshes their timeline
    // Just pull the timeline from the database
    return this.redisDatabase[id].timeline;
  }

  preview(id) {
    // preview of our datastore
    console.log(this.redisDatabase[id]);
  }
}

// Sample Usage

// setup instance
const Twitter = new FakeTwitter();
// create an account for me
Twitter.createUser("griffith");
// create an account for you
Twitter.createUser("eustace");
// add a new follower
Twitter.addFollower("griffith", "eustace");
// Record my tweet
Twitter.recordTweet("griffith", "Eustace is a hoe?");

// Inspect the whole object to see what's going on
console.log(Twitter);