Post Service - Angular

post.service.ts

import { Injectable } from '@angular/core';
import { Post } from './post.model';
import { Subject } from 'rxjs';
import { HttpClient } from '@angular/common/http';
import { map } from 'rxjs/operators';

@Injectable({providedIn: 'root'})
export class PostsService {
  private posts: Post[] = [];
  private postsUpdated = new Subject<Post[]>();

  constructor(private http: HttpClient) {}

  getPosts(){
    this.http.get<{message: string, posts: any}>('http://localhost:3000/api/posts')
      .pipe(map((postData) => {
        return postData.posts.map(post => {
          return {
            title: post.title,
            content: post.content,
            id: post._id
          };
        });
      }))
      .subscribe((transformedData) => {
        this.posts = transformedData;
        this.postsUpdated.next([...this.posts]);
      });
  }

  getPostUpdateListener() {
    return this.postsUpdated.asObservable();
  }

  addPost(title: string, content: string){
    const post: Post = {id: null, title: title, content: content};
    this.http.post<{message: string, postId: string}>('http://localhost:3000/api/posts', post)
      .subscribe((responseData => {
        const id = responseData.postId;
        post.id = id;
        this.posts.push(post);
        this.postsUpdated.next([...this.posts]);
      }));
  }

  deletePost(postId: string){
    this.http.delete('http://localhost:3000/api/posts/' + postId)
    .subscribe(() => {
      const updatedPosts = this.posts.filter(post => post.id !== postId);
      this.posts = updatedPosts;
      this.postsUpdated.next([...this.posts]);
    });
  }
}