Twitter Like System

Twitter.js

class Twitter {
    constructor() {
        this.users = {};
        this.tweets = [];
        this.followers = {};
    }

    postTweet(userId, content) {
        const tweet = {
            id: this.tweets.length,
            userId,
            content,
            likes: 0,
            timestamp: new Date().getTime()
        };
        this.tweets.push(tweet);

        if (!this.users[userId]) {
            this.users[userId] = [];
        }
        this.users[userId].push(tweet.id);

        return tweet.id;
    }

    likeTweet(userId, tweetId) {
        const tweet = this.tweets[tweetId];
        if (tweet) {
            tweet.likes++;
        }
    }

    dislikeTweet(userId, tweetId) {
        const tweet = this.tweets[tweetId];
        if (tweet) {
            tweet.likes--;
        }
    }

    getTopLikedTweets(userId, k = 10) {
        const userTweets = this.users[userId] || [];
        const sortedTweets = userTweets.map(id => this.tweets[id])
                                       .sort((a, b) => b.likes - a.likes);
        return sortedTweets.slice(0, k);
    }

    follow(userId, followeeId) {
        if (!this.followers[userId]) {
            this.followers[userId] = new Set();
        }
        this.followers[userId].add(followeeId);
    }

    unfollow(userId, followeeId) {
        if (this.followers[userId]) {
            this.followers[userId].delete(followeeId);
        }
    }

    generateNewsFeed(userId) {
        let newsFeed = [];
        
        const userTweets = this.users[userId] || [];
        newsFeed.push(...userTweets.map(id => this.tweets[id]));

        const followees = this.followers[userId] || new Set();
        followees.forEach(followeeId => {
            const followeeTweets = this.users[followeeId] || [];
            newsFeed.push(...followeeTweets.map(id => this.tweets[id]));
        });

        newsFeed.sort((a, b) => b.timestamp - a.timestamp);
        return newsFeed;
    }
}

// Example Usage
const twitter = new Twitter();

const userId1 = 'user1';
const userId2 = 'user2';

twitter.postTweet(userId1, 'Hello World!');
twitter.postTweet(userId1, 'Another tweet from user1');
twitter.postTweet(userId2, 'Tweet from user2');
twitter.likeTweet(userId1, 2);  // Like user2's tweet
twitter.likeTweet(userId2, 0);  // Like user1's tweet
twitter.likeTweet(userId2, 1);  // Like user1's tweet

twitter.follow(userId1, userId2);

console.log('User1 news feed:', twitter.generateNewsFeed(userId1));
console.log('User2 news feed:', twitter.generateNewsFeed(userId2));

console.log('Top liked tweets for user1:', twitter.getTopLikedTweets(userId1, 1));

twitter.unfollow(userId1, userId2);

console.log('User1 news feed after unfollowing user2:', twitter.generateNewsFeed(userId1));