Unwrapped todos

app.component.ts

import { Component } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { OnInit } from '@angular/core';
import { map } from 'rxjs/operators';
import { Observable } from 'rxjs';

interface Todo {
  userId: number
  id: number
  title: string
  completed: boolean
}

interface UnwrappedTodo {
  title: string
  id: number
}

type UnwrappedTodos = UnwrappedTodo[];

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
  
  title = 'angular-tests';
  unwrappedTodos: UnwrappedTodos;

  constructor(private http: HttpClient) {}

  getTodos(): Observable<Todo[]> {
    return this.http.get<Todo[]>('https://jsonplaceholder.typicode.com/todos/');
  }

  unwrapTodo({title, id}: Todo): UnwrappedTodo {
    return {title, id};
  }

  unwrapTodos() {
    return (source: Observable<Todo[]>) => {
      return source.pipe(
        map((todos: Todo[]) => todos.map((todo: Todo) => this.unwrapTodo(todo)))
      )
    }
  }

  setUnwrappedTodos(unwrappedTodos: UnwrappedTodos) {
    this.unwrappedTodos = unwrappedTodos;
  }

  ngOnInit() {
    this.getTodos()
      .pipe(this.unwrapTodos())
      .subscribe((unwrappedTodos: UnwrappedTodos) => {
        this.setUnwrappedTodos(unwrappedTodos);
        console.log(this.unwrappedTodos);
      });
  }

}

https://stackoverflow.com/questions/42238819/angular-2-how-to-call-a-function-after-get-a-response-from-subscribe-http-post