我在组件 Angular 8 中调用服务未定义

Question

I have created an interface and a service in which this service is responsible for getting some data from API but when I try to call that from a component, it returns undefined to me. these are my services and my component (I have also noticed that the function within the service returns void and I have provided them in app.module )

@Injectable()
export class TasksService {
compeletedTasks: Task[]
constructor(public http: Http) { }
getCompeletedTasks(){
this.http.get("http://localhost:4000/api/compeleted").subscribe(response =>{
this.compeletedTasks = response.json()
return response.json()})}
}

and this is my component:

import { TasksService } from '../../services/tasks.service';
export class DoneTaskItemsComponent implements OnInit {
constructor(private tasksService:TasksService){}

ngOnInit() {
    console.log(this.tasksService.getCompeletedTasks())}
}

I have just deleted things like @component and other things for more readable of codes

So any solution for that? I need to use the compeletedTasks on the template but for now, when I log them on the console, I get undefined

Answer 1

As @Challappan says you need to use httpClient instead of http for making api requests.

Try to change code like below.

getCompeletedTasks(){
   return this.http.get("http://localhost:4000/api/compeleted");
}

In component like below.

compeletedTasks: Task[]

ngOnInit() {
    this.tasksService.getCompeletedTasks().subscribe(response => {
         this.completedTasks = response;
    });
}

This link might help.

angular httpClient api example medium