CODEWITHSUNDEEP
angulartypescriptobservable
topvova
topvova

Reputation: 71

Generic type Observer<T> requires 1 types argument(s)

I try to understand Observable in Angular 4. I am watching a video about it and I want to create my first Observable, but get an error in my IDE:

Generic type Observer requires 1 types argument(s)

My code:

import { Component, OnInit } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import 'rxjs/Rx';
import { Observer } from 'rxjs/Observer';

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

export class HomeComponent implements OnInit {

  constructor() { }

  ngOnInit() {
    const myObservable = Observable.create((observer: Observer) => {
        setTimeout(() => {
            observer.next('first package');
        }, 2000);
    });
  }

}

I guess that I should add generic type like this: Observable<any>, but in the video which I watched the author don't add any generics and it works. Can anyone explain me why?

Upvotes: 1

Views: 4761

Answers (1)

mcguiretj
mcguiretj

Reputation: 61

Your error is telling you exactly what to do. Generic type Observer requires 1 types argument(s). You just need to pass the data type that are using for your Observer. In this case it's a string 'first package'. So, in your .create() method set the observer data type to a string like this:

observer: Observer<string>

Upvotes: 2

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