Angular rxjs Observer Generic Type required 1 argument

Question

I am facing following error while using Observers with Observables from rxjs package.

ERROR in src/app/home/home.component.ts(25,57): error TS2314: Generic type 'Observer' requires 1 type argument(s).

I am trying to create my first Observable

const myObservable = Observable.create((observer: Observer) => {
setTimeout(() =>{observer.next('first package');},2000);
setTimeout(() =>{observer.next('second package');},4000);
setTimeout(() =>{observer.next('this does not work');},5000);
 });

Can you suggest, what could be the possible solution ?

https://stackoverflow.com/questions/41757684/generic-type-observablet-requires-1-type-argument this link will help you or put some code here, thanks — kushal shah, Dec 25 '19 at 10:02

score 2 · Accepted Answer · answered Dec 25 '19 at 10:10

As @Eldar mentioned in the comment Observer interface expects generic type

interface Observer<T> {
  closed?: boolean;
  next: (value: T) => void;
  error: (err: any) => void;
  complete: () => void;
}

Change your Observer interface to Observer<string>

const myObservable = Observable.create((observer: Observer<string>) => {
   setTimeout(() =>{observer.next('first package');},2000);
   setTimeout(() =>{observer.next('second package');},4000);
   setTimeout(() =>{observer.next('this does not work');},5000);
 });

score 1 · Answer 2 · answered Dec 25 '19 at 10:10

const myObservable = Observable.create((observer: Observer<string>) => {
       setTimeout(() =>{observer.next('first package');},2000);
       setTimeout(() =>{observer.next('second package');},4000);
       setTimeout(() =>{observer.next('this does not work');},5000);
});

Angular rxjs Observer Generic Type required 1 argument

2 Answers2