Add allowUpdates prop on Camera

[naftalibeder]

Description

Adds an optional allowUpdates boolean prop to Camera which, if false, causes the camera to return early before communicating with the native camera module.

This is intended for situations where the map is not visible (including if the app is in the background), and it would be preferable to avoid moving the camera - and therefore fetching new tiles, or causing the markers on the map to change - without actually hiding the map, which can cause undesirable behavior when the map reappears.

The only reasonable alternative is to "freeze" all props before sending them to Camera, which adds a bit more complicated logic to the enclosing app.

Checklist

• I have tested this on a device/simulator for each compatible OS
• I formatted JS and TS files with yarn lint
• I updated the documentation yarn generate
• I mentioned this change in CHANGELOG.md
• I updated the typings files (index.d.ts)
• I added/ updated a sample (/example)

Screenshot OR Video

TODO

[naftalibeder]

@ferdicus What do you think about this? We've been working around this for a pretty long time, and I think this would greatly simplify how an app needs to handle this situation. I know this prop doesn't have a corresponding config in the native modules, but it is specific to React logic (e.g. you can't "early return" in declarative code).

[ferdicus]

Looks good to me, optional after all 👍🏿

Do you have an example of how/ when you're using this?

[naftalibeder]

Yep, we do:

<Camera
  ...
  allowUpdates={appStateIsActive || pictureInPicture}
/>

(The picture-in-picture conditional is for Android.)

[ferdicus]

thanks

[ferdicus]

@naftalibeder, this is failing tests after merge (sorry, didn't catch it earlier - forked PRs don't run actions 😞 ):

[naftalibeder]

Sorry about that - fixed here.

Maybe the default PR checklist should include yarn run unittest?

[ferdicus]

Sorry about that - fixed here.

Maybe the default PR checklist should include yarn run unittest?

Good thing you mentioned it - I've added an additional todo in #1631 (sorry.... 😞 )