Angular: How to get value from one component's frontend (app.compont.html) to another component's backend (other.component.ts)

Question

Consider a simple crud scenario. I have a lot of input fields and buttons in app.component.html. When i press a button from app.component.html, it will send html field value to 'other.component.ts' component and will display the result back in app.component.html after processing (like add, subtract or other).

Here is app.component.html

<a routerLink="posts/">Show Posts</a>
<input type="number" [(ngModel)]="get-one-post-id">
<a routerLink="/post-by-id">Show One Posts</a>


<router-outlet>

</router-outlet>

post-by-id-component.ts

import { Component, OnInit } from '@angular/core';
import { DataService } from '../data.service';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-post-by-id',
  templateUrl: './post-by-id.component.html',
  styleUrls: ['./post-by-id.component.css']
})
export class PostByIdComponent implements OnInit {

  posts: object;
  constructor(private dataService: DataService) { }

  ngOnInit(): void {
    // const id = ??
    this.GetPost(1);
  }

  async GetPost(id: number)
  {
    const response = await this.dataService.Get_A_Post(id);
    const dataService = await response.json();
    this.posts = dataService;
  }

}

post-by-id-component.html

<div *ngFor="let post of posts">
  <h3>{{post.title}}</h3>
  <p>{{post.body}}</p>
</div>

I just want to get value from the field called get-one-post-id from app.component.html to post-by-id-component.ts [where I commented // const id = ??]. But i can't find a way to import it.

Answer 1

To share Data between Angular Components exists 4 different ways:

1. Parent to Child: Sharing Data via Input

2. Child to Parent: Sharing Data via ViewChild

3. Child to Parent: Sharing Data via Output() and EventEmitter
4. Unrelated Components: Sharing Data with a Service

You can read this useful article to see how it works.