$Enum type declaration causes flow error

[andrewtremblay-pear]

Bug

In previous versions of PushNotificationIOS, types were declared with $Keys

https://github.com/facebook/react-native/blob/76ff31616e0b569d775c7156d8bc211d09a65fe9/Libraries/PushNotificationIOS/PushNotificationIOS.js#L39

export type PushNotificationEventName = $Keys<{

However the same type in the react-native-community location seems to be using $Enum :
https://github.com/react-native-community/react-native-push-notification-ios/blame/56cae07e2a179ff5bd4ebb5df417f324f8eb17c3/js/index.js#L38

export type PushNotificationEventName = $Enum<{

This is causing a flow error when updating imports:

Error ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ node_modules/@react-native-community/push-notification-ios/js/index.js:38:41

Cannot resolve name $Enum.

     35│ /**
     36│  * An event emitted by PushNotificationIOS.
     37│  */
     38│ export type PushNotificationEventName = $Enum<{
     39│   /**
     40│    * Fired when a remote notification is received. The handler will be invoked
     41│    * with an instance of `PushNotificationIOS`.

Environment info

React native info output:

info
  React Native Environment Info:
    System:
      OS: macOS 10.14.6
      CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
      Memory: 159.62 MB / 32.00 GB
      Shell: 3.2.57 - /bin/bash
    Binaries:
      Node: 8.11.3 - ~/.nvm/versions/node/v8.11.3/bin/node
      Yarn: 1.10.1 - ~/.nvm/versions/node/v8.11.3/bin/yarn
      npm: 5.6.0 - ~/.nvm/versions/node/v8.11.3/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.4, macOS 10.14, tvOS 12.4, watchOS 5.3
      Android SDK:
        API Levels: 14, 16, 19, 23, 24, 25, 26, 27, 28
        Build Tools: 19.1.0, 20.0.0, 21.1.2, 22.0.1, 23.0.1, 25.0.2, 26.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.2, 28.0.3, 29.0.0, 29.0.1
        System Images: android-22 | Google APIs Intel x86 Atom, android-28 | Google Play Intel x86 Atom_64
    IDEs:
      Android Studio: 3.4 AI-183.6156.11.34.5522156
      Xcode: 10.3/10G8 - /usr/bin/xcodebuild
    npmPackages:
      react: ^16.8.6 => 16.9.0
      react-native: 0.59.10 => 0.59.10
    npmGlobalPackages:
      create-react-native-app: 2.0.2
      react-native-cli: 2.0.1
      react-native-create-library: 3.1.2
      react-native-git-upgrade: 0.2.7

Library version: 0.59.10

Steps To Reproduce

1. create a react-native-application with the following dependencies
   https://gist.github.com/andrewtremblay-pear/518218ac326f8433faa83b6aa110f30f

2. npm run flow
   ...

Describe what you expected to happen:

1. Flow checks to pass or $Enum to be recognized

Reproducible sample code

Sample code repo can be provided, not sure if this is just an obvious error on my part. Googling for $Enum provides no helpful results so I'm guessing it's an undocumented additional dependency.

[JoeM-RP]

FWIW, the legacy PushNotificationIOS switched from $Enum to $Keys in May and has remained as such since. facebook/react-native@f050f99#diff-c4441933746f851b6a89a445751b812c

It's curious that the community branch would go the other way. Running the community push notifications repo locally, I don't get a flow error on $enum until updating to flow 0.106.3 from 0.86.0

[Naturalclar]

Fixed via #28