Mechanism for removing connection `onClose` callback
viglucci opened this issue · comments
We can register a callback with an RSocket
using the onClose
method. We do not currently have any way to deregister a previously registered callback.
Motivation
I'm sure there are other use cases, however, this would be useful when paired with the useEffect
hook in React, which expect to be able to "undo" registrations and side-effects.
useEffect(() => {
const id = rsocket.onClose((e) => {
console.log(e);
});
return () => {
rsocket.removeCloseListener(id);
};
}, [rsocket]);
Desired solution
RSocket
, likely through Closeable
, could be extended to allow deregistration of callbacks. This might be best with having Closeable
more closely resemble event emitter APIs.
// add a listener
const id = rsocket.onClose.addEventListener(() => {...});
// remove a listener
rsocket.onClose.removeEventListener(id);
Considered alternatives
Rsocket.onClose
could implement/expose an observable that would natively support subscriptions. This could use existing types such as Cancellable
and OnTerminalSubscriber
.