I am in the process of upgrading to rxjs v6 from 5, I have also upgraded my typescript version from 2.9.2 to 3.7.4. In one of my angularjs components, I make a call to a service that returns a promise. For ease of use, I convert that into an observable in my component by using the from rxjs function. My code looks like this (with names changed from originals).

```
saveObject(name: string): Observable<void> {
    return from(
            this.myService.saveMyObject(name)
                .then(() => {
                    //Show Save success on ui
                    return;
            }),
        )
        .pipe(
            catchError((error) => {
                // error handling logic
                return of(); // this bit was an attempt to fix the problem
            }),
        );
}

```

The problem I am having is that the saveObject function in the component returns an observable of void, the promise ultimately resolves to void but when I try to return the observable I get an error saying that observable< unknown> is not assignable to observable< void>. Why is typescript/rxjs inferring the type to be unknown and is there anything I can do aside from doing type assertion to get the correct type.

Edit: Removing the pipe altogether does not fix the issue, just the from(promise) is enough to get the error, unfortunately even doing this to tell rxjs that it is an promise of void does not help, it still offers the same error.

```
from<Promise<void>>(//promiseCode)

```