Property ‘timer’ does not exist on type ‘typeof observable’

This error message suggests that the property timer is being accessed on a variable with the type observable, but the timer property does not exist on that type.

An example of this error can be seen in the following code:

        
            import { Observable } from 'rxjs';
        
            const myObservable: Observable = new Observable((observer) => {
                const id = setInterval(() => {
                    observer.next(4);
                }, 1000);
        
                return () => {
                    clearInterval(id);
                };
            });
        
            myObservable.timer(5000).subscribe((val) => console.log(val));
        
    

In the above code, myObservable is an instance of the Observable class from the RxJS library. The timer method is being called on myObservable, which is causing the error because the timer property does not exist on the Observable type.

To fix this error, you need to use the correct method or property for achieving the desired functionality. In this case, if you want to delay the emission of values from the observable by a certain duration, you can use the delay operator or the timer function from RxJS.

Here’s an updated example using the delay operator to delay the emission by 5 seconds:

        
            import { Observable } from 'rxjs';
            import { delay } from 'rxjs/operators';
        
            const myObservable: Observable = new Observable((observer) => {
                const id = setInterval(() => {
                    observer.next(4);
                }, 1000);
        
                return () => {
                    clearInterval(id);
                };
            });
        
            myObservable.pipe(delay(5000)).subscribe((val) => console.log(val));
        
    

In this updated code, the pipe method is used to apply the delay operator to the observable. The delay operator delays the emission of values from the observable by the specified duration (in this case, 5 seconds). Therefore, the value will only be emitted after the delay of 5 seconds.