The object has an unspecified type

I have a simple Rxjs function involving observables and operators to return a new observable. In my code, I am using filter and map operators chained inside a pipe. Unfortunately, I am receiving the error TS2571: Object is of type 'unknown' inside the filter operator for data. The code is as follows:

import { filter, map, Observable } from 'rxjs'

@Component({
  selector: 'app-observable-operator',
  templateUrl: './observable-operator.component.html',
  styleUrls: ['./observable-operator.component.css']
})
export class ObservableOperatorComponent{

  title:string='Angular Observable using Observable Operators';

  ob=new Observable((observer:any)=>{
    console.log("Observable Starts");
    observer.next(1)
    observer.next(2)
    observer.next(3)
    observer.next(4)
    observer.next(5)
    observer.complete()
  }).pipe(filter(data=>
    data > 2), //Error inside filter operator (parameter) data:unknown
    map((val)=>{return val as number*2}),

  )

}


Answer №1

In my opinion, it seems necessary to include typing in the parameter

filter((value: any) => value > 2)

Answer №2

To resolve the issue at hand, it is crucial to accurately specify the type of the observer.

The observer parameter within the function provided to the Observable constructor should be declared as type Observer<number>, given that it deals with notifying numbers. By doing so, Typescript will be able to deduce the type of data as number.

In essence, the code should be adjusted as follows:

ob = new Observable((observer: Observer<number>) => {
  console.log("Observable Starts");
  observer.next(1)
  observer.next(2)
  observer.next(3)
  observer.next(4)
  observer.next(5)
  observer.complete()
}).pipe(filter(data =>
  data > 2), //Error inside filter operator (parameter) data:unknown
  map((val) => {return val as number*2}),
)

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