Passing data with service

// model
// ts
export interface Post {
  // some data for example
  title: string;
  content: string;
}

// service
// ts
import { Post } from 'path to post model';

@Injectable({provadedIn: 'root'}) // read the comment at the bottom
export class PostService {
  private posts: Post[] = [];
  
  getPosts() {
    return this.posts;
  }
  
  addPosts(title: string, content: string) {
    const post: Post = {
      title: title,
      content: content
    }
    this.posts.push(post);
  }
}

// component 1
//ts
import { PostService } from 'path to post service';

export class className implements OnInit {
  constructor(public postsService: PostsService) {}
  
  onAddPost(form: NgForm) { // for html and detailed form explanation look snippet "Data from From with validation"
    if (form.invalid) {
      return;
    }
    this.postsService.addPost(form.value.title, form.value.content);
  }
  
}
// component 2
// ts
import { Post } from 'path to post model';
import { PostService } from 'path to post service';

export class className implements OnInit {
  posts: Post[] = [];

  // this is a short version of 
  constructor(public postsService: PostsService) {}
  // of this
  /*
  postService: PostService;
  constructor(postsService: PostsService) {
      this.postsService = postsService;
  }
  */
  
  ngOnInit() {
    this.posts = this.postsService.getPosts();
  }
}


// ********** //
// // @Injectable({provadedIn: 'root'}) this is the same as insert service in app.module.ts under providers