reduce object creation by useMemo

[leoyli]

Hi, thank you for creating this amazing library!

I've noticed there are some performance improvements can be done by using useMemo in useEventCallback hook. The change basically leverage the lazy evaluations and reduce new object creations at run-time.

Thank you!

[Brooooooklyn]

Please squash your commits, and edit your commit follow the guide: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#-commit-message-guidelines

[leoyli]

@Brooooooklyn, thanks fixed.

[Brooooooklyn]

unit test failed in circleci @leoyli

[leoyli]

@Brooooooklyn, is that due to the code is running under react 16.9, based on the release post, there are some change in the testing utility?! I changed nothing but squash my commits, last time it passed.

[Brooooooklyn]

It's React 16.9 already in master branch, and all tests were passed.
So could you please double check your changes and pass the tests in your local machine?

[BlackHole1]

@leoyli @Brooooooklyn Change the code to the following to pass the test:

- const returnedCallback = useCallback((e: EventValue) => event$.next(e), [event$]) + function eventCallback(e: EventValue) { + return event$.next(e) + } + const returnedCallback = useCallback(eventCallback, [event$])

https://github.com/LeetCode-OpenSource/rxjs-hooks/pull/65/files#diff-a4eb4268013ae7511c07e3266bf23937R62

[Miloas]

Closed because of 9b86698