JS-Advanced Exams: Article

class Article {
  constructor(title, creator) {
    this.title = title;
    this.creator = creator;
    this._comments = [];
    this._likes = [];
  }

  set likes(x) {
    this._likes = x;
  }

  set comments(x) {
    this._comments = x;
  }

  get likes() {
    let hasLikesArr = this._likes.filter(x => x.likes === 1);

    if (hasLikesArr.length === 0) {
      return `${this.title} has 0 likes`;
    } else if (hasLikesArr.length === 1) {
      let result = "";
      this._likes.forEach(
        user => (result += `${user.username} likes this article!\n`)
      );
      return result.trim();
    } else {
      let firstLike = hasLikesArr[0].username;
      let totalLikes = hasLikesArr.length - 1;
      return `${firstLike} and ${totalLikes} others like this article!`;
    }
  }

  like(username) {
    const user = this._likes.find(u => u.username === username);

    if (user) {
      throw new Error("You can't like the same article twice!");
    }

    if (this.creator === username) {
      throw new Error("You can't like your own articles!");
    }

    this._likes.push({ username: username, likes: 1 });

    return `${username} liked ${this.title}!`;
  }

  dislike(username) {
    const user = this._likes.find(u => u.username === username);

    if (!user) {
      throw new Error("You can't dislike this article!");
    }

    user.likes--;

    return `${username} disliked ${this.title}`;
  }

  comment(username, content, id) {
    const comment = this._comments.find(c => c.id === id);

    if (comment === undefined) {
      this._comments.push({
        id: this._comments.length + 1,
        username: username,
        content: content,
        replies: []
      });
      return `${username} commented on ${this.title}`;
    }

    comment.replies.push({
      id: id + (comment.replies.length * 0.1 + 0.1),
      username: username,
      content: content
    });

    return "You replied successfully";
  }

  toString(sortingType) {
    let result = `Title: ${this.title}\nCreator: ${this.creator}\nLikes: ${
      this._likes.filter(x => x.likes === 1).length
    }\nComments:\n`;

    this._comments.sort(sortByCriteria).forEach(comment => {
      addToResult(comment, "comment");
      comment.replies
        .sort(sortByCriteria)
        .forEach(reply => addToResult(reply, "reply"));
    });

    function sortByCriteria(a, b) {
      const map = {
        asc: () => a.id - b.id,
        desc: () => b.id - a.id,
        username: () => a.username.localeCompare(b.username)
      };

      return map[sortingType]();
    }

    function addToResult(typeObj, type) {
      const map = {
        comment: () =>
          (result += `-- ${typeObj.id}. ${typeObj.username}: ${typeObj.content}\n`),
        reply: () =>
          (result += `--- ${typeObj.id}. ${typeObj.username}: ${typeObj.content}\n`)
      };

      return map[type]();
    }

    return result.trim();
  }
}