There are instances where the outcome of an asynchronous operation holds no significance, leading to method signatures in async operations specifying Observable<any> or Promise<any> as the return value.
Illustration
For instance, the Ionic2 NavController outlines:
/** // ...
* @returns {Promise} Returns a promise which is resolved when the transition has completed.
*/
abstract remove(/* ... */): Promise<any>;
Without delving into the actual implementation, it remains uncertain whether any value (e.g. null or undefined) is emitted, and if there is any valuable information that can be extracted from those values.
Inquiry: Observable<void>?
The concept of Observable<void> or Promise<void> seems rare. It could provide clarity regarding the absence of any useful output. Are there any technical impediments preventing the use of the void type with observables? Or is there a specific reason why this approach isn't commonly adopted to denote empty values?