Angular - constructor implementation is missing

Question

Following a tutorial, I am trying to inject a service in my component:

import { Component } from '@angular/core';
import { TodoService } from './todos.service';
import { ITodo } from './todo';
import { Http , Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';

@Component({
  selector: 'my-app',
  templateUrl: `app/app.component.html`,
  providers: [TodoService]
})
export class AppComponent  
{ 
  itodos: ITodo[];
  appTitle: string = 'To Do App';
  constructor(private _todo: TodoService);

  ngOnInit() : void {
     this._todo.gettodos()
     .subscribe(itodos => this.itodos = itodos);
  }
}

When calling TodoService, I get 'constructor implementation is missing'

My Service:

import { Injectable } from '@angular/core';
import { Http , Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/do';
import { ITodo } from './todo';

@Injectable()
export class TodoService {
   private _todoUrl='app/todos.json';
   constructor(private _http: Http){}

   gettodos(): Observable<ITodo[]> {
      return this._http.get(this._todoUrl)
      .map((response: Response) => <ITodo[]> response.json())
      .do(data => console.log(JSON.stringify(data)));
   }
}

What do I need to do to clear the error, since my TodoService is using Http?

Replace constructor(private _todo: TodoService); with constructor(private _todo: TodoService) { }. — Martin Parenteau
– Martin Parenteau, Commented Jun 21, 2018 at 0:46
Just to note, the Http service has been replaced with the HttpClient service (and corresponding module), so depending on your Angular version the tutorial may be out of date with what you've installed. — Phix
– Phix, Commented Jun 21, 2018 at 0:47

Titian Cernicova-Dragomir · Accepted Answer · 2018-06-21 00:47:59Z

9

Your constructor does not have a body, just provide an empty body if you don't want to have any extra code in the constructor

constructor(private _todo: TodoService){}

answered Jun 21, 2018 at 0:47

Titian Cernicova-Dragomir

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