Refactor CommentsRepository and CommentsService for enhanced comment retrieval

- Add a new method in CommentsRepository to find comments by article ID, optimized to include author details and their followers.
- Simplify comment mapping in CommentsService to directly include author information, greatly improving performance from O(n*(k+t)) to O(n).

Author: yamcodes

src/articles/comments/comments.repository.ts

@@ -1,7 +1,6 @@
-import { and, desc, eq } from 'drizzle-orm';
-
 import type { Database } from '@/database.providers';
 import { articles, comments } from '@articles/articles.model';
+import { and, desc, eq } from 'drizzle-orm';
 import type { CommentToCreate } from './comments.schema';
 
 export class CommentsRepository {
@@ -35,10 +34,31 @@ export class CommentsRepository {
     return result;
   }
 
+  /**
+   * Find all comments by article id
+   *
+   * Note: this operation is optimized to include the author and their followers.
+   * Use it with caution. If you need something simpler, consider refactoring this method and making the "with" option dynamic.
+   * @param articleId - The id of the article
+   * @returns An array of comments
+   */
   async findManyByArticleId(articleId: number) {
     const result = await this.db.query.comments.findMany({
       where: eq(comments.articleId, articleId),
       orderBy: [desc(comments.createdAt)],
+      with: {
+        author: {
+          columns: {
+            id: true,
+            username: true,
+            bio: true,
+            image: true,
+          },
+          with: {
+            followers: true,
+          },
+        },
+      },
     });
     return result;
   }

src/articles/comments/comments.service.ts

@@ -63,24 +63,20 @@ export class CommentsService {
       article.id,
     );
 
-    const returnedComments = await Promise.all(
-      comments.map(async (comment) => {
-        const authorProfile = await this.profilesService.findByUserId(
-          currentUserId ?? null,
-          comment.authorId,
-        );
-
-        return {
-          id: comment.id,
-          body: comment.body,
-          createdAt: comment.createdAt,
-          updatedAt: comment.updatedAt,
-          author: authorProfile.profile,
-        };
-      }),
-    );
-
-    return returnedComments;
+    return comments.map((comment) => ({
+      id: comment.id,
+      body: comment.body,
+      createdAt: comment.createdAt,
+      updatedAt: comment.updatedAt,
+      author: {
+        username: comment.author.username,
+        bio: comment.author.bio,
+        image: comment.author.image,
+        following: currentUserId
+          ? comment.author.followers.some((f) => f.followerId === currentUserId)
+          : false,
+      },
+    }));
   }
 
   async deleteComment(