Expo & Bare RN haptic interop

[jxom]

Based on the discussion in #1.

It would be nice to have the ability to support haptic feedback in Expo managed projects (as well as bare React Native projects – which is what we support currently).

I think the ideal approach is @andreialecu's module detection technique. We should list expo-haptics (for Expo managed projects) and react-native-haptic-feedback (for bare RN projects) as optional peer dependencies, and if the library detects that expo-haptics is installed, then prefer that over react-native-haptic-feedback.

[andreialecu]

I just made an attempt to implement this but it seems that optional requires are broken in the latest Metro for some weird reason.

I've been running into:

Error: Requiring unknown module "undefined". If you are sure the module exists, try restarting Metro. You may also want to run `yarn` or `npm install`.

This seems to be tracked at: facebook/metro#666

Disabling inlineRequires didn't work, and doesn't seem like a good idea anyway.

So I think an alternative would be to simply remove the haptics implementation from the library and just provide a callback which the user can handle themselves to trigger haptics.

Meaning, instead of enableHapticFeedback, there would be a callback onHapticFeedback.

Or it could be more generic, so that the user could do:
onCurrentXChange={(value) => { if (value !== 0) { invokeHaptic() }}

[nandorojo]

The onActivated and onEnded props are no-ops at the moment. I can PR this.

Actually I can't seem to figure out why this is.