Facebook System ( list/ map outside of the class)

gistfile1.txt

class User {
    constructor(userId, userName) {
        this.userId = userId;
        this.userName = userName;
    }
}

class Post {
    constructor(userId, posts) {
        this.userId = userId;
        this.posts = posts;
    }
}

class Friend {
    constructor(follower, followee) {
        this.follower = follower;
        this.followee = followee;
    }
}

const users = new Map();
const friends = [];
const posts = [];

function registerUser(userId, userName) {
    if (!users.has(userId)) {
        const newUser = new User(userId, userName);
        users.set(userId, newUser);
        return newUser;
    }
    return "User already existed";
}

function addFriend(userId, friendId) {
    friends.push(new Friend(userId, friendId));
    friends.push(new Friend(friendId, userId));
    return "Added as friend";
}

function removeFriend(userId, friendId) {
    friends = friends.filter(friend => !(friend.followee === userId && friend.follower === friendId));
    friends = friends.filter(friend => !(friend.followee === friendId && friend.follower === userId));
    return "Unfriended successfully";
}

function addPost(userId, postContent) {
    posts.push(new Post(userId, postContent));
    return "Added post successfully";
}

function getFriendPosts(userId) {
    const friendList = friends.filter(eachUser => eachUser.follower === userId).map(friend => friend.followee);
    return posts.filter(post => friendList.includes(post.userId));
}

function searchFriendPosts(userId, search) {
    const friendList = friends.filter(eachUser => eachUser.follower === userId).map(friend => friend.followee);
    const postList = posts.filter(post => friendList.includes(post.userId));
    return postList.filter(post => post.posts.toLowerCase().includes(search.toLowerCase()));
}

// Usage example:
registerUser(1, 'Tanvir');
registerUser(2, 'Nadim');

addFriend(1, 2);

addPost(1, 'Hello, friends!');
addPost(2, 'Hi, Bangladesh!');

console.log("friendPost", getFriendPosts(1));
console.log("friendPost search", searchFriendPosts(1, "bangladesh"));
removeFriend(1, 2);