The RxJS operator map can be used to map the stream value to a new value. However, if you want to map to a static value that does not depend on the stream value, you can use the mapTo operator. This operator accepts the value directly and you don't need to create an additional function.

// Use `map` for dynamic values
stream$.pipe(map((user) => user.isAdmin));

// Use `mapTo` for static values

Note: the mapTo operator has been deprecated in RxJS 7 and will be removed in RxJS 8. It's better to use map with a function that returns the static value.