Using a repository to fetch the read models

The repository often contains a variety of service methods that perform different queries against the model.

For example, in the IPostRepo interface, we define methods for getting all recent posts by calling getRecentPosts (offset?: number), and a similar one for getting popular posts as well.

These methods exist solely so that the Query use case can do its job.

// forum/repos/postRepo.ts

import { Post } from "../domain/post";
import { PostId } from "../domain/postId";
import { PostDetails } from "../domain/postDetails";

export interface IPostRepo {
  getPostDetailsBySlug (slug: string): Promise<PostDetails>;
  getPostBySlug (slug: string): Promise<Post>;
  getRecentPosts (offset?: number): Promise<PostDetails[]>;
  getPopularPosts (offset?: number): Promise<PostDetails[]>;
  getNumberOfCommentsByPostId (postId: PostId | string): Promise<number>;
  getPostByPostId (postId: PostId | string): Promise<Post>;
  exists (postId: PostId): Promise<boolean>;
  save (post: Post): Promise<void>;
  delete (postId: PostId): Promise<void>;

In each of these methods, you'd…

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