Unable fetch the api's data

Question

I have an component called customer which is used to display some data using the api.

For calling the api i have created a file called services.ts and it's CODE looks like this:

services.ts

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
import { IPosts } from './models';

@Injectable()
  export class Service {
      constructor(private http: HttpClient) {}

   public getContactList(): Promise<IPosts> {
    const apiUrl: string = 'https://jsonplaceholder.typicode.com/posts'; // dummy API

    return this.http.get<IPosts>(apiUrl).toPromise();
   }
 }

As shown in the code an interface (IPosts),I have declared this interface(i,e IPosts) inside an file called models.ts. The CODE looks like this:

   export interface IPosts {
    userId: number;
    id:     number;
    title:  string;
    body:   string;
    }

Now i am displaying this api's data incustomer component is like this:

customer.html

   <div class="container">
        <h3>Blog Posts:</h3>
      <div class="blogPost " *ngFor = "let post of posts">
           <p>{{post.title}}</p>
           <p>{{post.body}}</p>
           <hr>
      </div>
  </div>

customer.ts

  import { Component, OnInit } from '@angular/core';
  import { Service } from '../service';
  import { map } from 'rxjs/operators';
  import { IPosts } from '../models';

  @Component({
   selector: 'app-customer',
   templateUrl: './customer.component.html',
   styleUrls: ['./customer.component.css']
  })

  export class CustomerComponent implements OnInit {
          constructor(public customersServiceList: Service) {}

  public async ngOnInit(): Promise<void> {
    const posts : IPosts = await this.customersServiceList.getContactList();
    console.log(posts);
    }

  }

I am able see the api's data in the console:

But unable to display it in .html file . What's wrong in calling the api.
Here is the stckblitz DEMO

Answer 1

Change CustomerComponent like this

export class CustomerComponent implements OnInit {

  constructor(public customersServiceList: Service) {}
  posts : IPosts[];
  public async ngOnInit(): Promise<void> {
      this.posts  = await this.customersServiceList.getContactList();
      console.log(this.posts);
   }
 }

Service

 public getContactList(): Promise<IPosts[]> {

    const apiUrl: string = 'https://jsonplaceholder.typicode.com/posts';
    return this.http.get<IPosts[]>(apiUrl).toPromise();
  }

It's working check here StackBlitz