Allow bypassing the observer

[GreenGremlin]

...by not passing a ref option.

Putting up this PR early for feedback. Tests are still needed.

I would like to use use-resize-observer, without adding the polyfill. This change makes that possible by not initializing the observer, if no ref is passed.

[GreenGremlin]

Removing the dependency array is necessary, in case ref is passed as null, then later passed as a valid value. This should not affect performance though, because the effect bails once the observer is created.

[GreenGremlin]

I've added a test to assert that a ResizeObserver is not initialized, if no ref is passed.

[GreenGremlin]

Is there anything I can do the help get this PR merged?

[ZeeCoder]

Sorry I just don't have time to review things right now. Maybe sometime next week.

…

On Mon, 27 Jul 2020, 23:40 Jonathan Felchlin, ***@***.***> wrote: Is there anything I can do the help get this PR merged? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#42 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA4CKEXDWTKSGWZCEHWBNUTR5XX4XANCNFSM4PEED3IQ> .

[GreenGremlin]

@ZeeCoder I don't mean to be a pest, but is there any chance you might have some time to look at this PR any time soon?

[ZeeCoder]

There are a couple issues with the proposed code changes here:

• The tests are failing in a number of places.
• Checking the RO instance on each effect run would be fine, but does not actually matter, since the subscriber effect after it will only run when the ref object instance changes,
• The added test does not actually cover the above case where you set the ref to null first, then to a valid ref to start measuring.
• Passing in null is possible currently (the TS types do not seem to support this though at the moment), but properly allowing null in a way that doesn't create an RO instance means we have to opt out of the hook providing the default ref as well, which it currently does, whenever the ref is falsy. (this is a breaking change.)

I've created a new PR based on your needs.
Still a WIP, but will cover your use case and have the above points addressed as well:
#44

Essentially the hook would consider "null" as a special ref param, which would signal for the hook that you might pass a real ref in later for observation, but for the time being you don't need it, and so a ResizeObserver instance would not be necessary either until then.

[ZeeCoder]

Addressed in: https://github.com/ZeeCoder/use-resize-observer/releases/tag/v6.2.0-alpha.1