Flow type for specific React Native events?

Question

In order to flowtype events, I define custom types like the following:

export type OnScrollEvent = {
  nativeEvent: {
    contentOffset: {
      y: number
    },
    contentSize: {
      height: number
    }
  }
}

Obviously, there are several missing properties (like x and width), but I have no need for them yet.

I have tried to locate similar types for RN but only found an Event type that does not seem to be particularly useful:

import type {Event} from "react-native";

handleEvent = (e: Event) => console.log(e.inexistentProperty)  // Flow doesn't care!

Are there any existing flow types for React Native events or do I have to keep defining them myself?

Update

They seem to be scattered around the code base. Here's the layout event type:

export type ViewLayout = {
  x: number,
  y: number,
  width: number,
  height: number,
}

export type ViewLayoutEvent = {
  nativeEvent: {
    layout: ViewLayout,
  }
}

found in ViewPropTypes.js

Answer 1

Since they are exported in ViewPropTypes you can use

import type { ViewLayoutEvent } from 'react-native/Libraries/Components/View/ViewPropTypes';

Answer 2

You'll need to play a bit of detective (as you've noticed). There are a few event types in the following location.

import {type ScrollEvent} from "react-native/Libraries/Types/CoreEventTypes";

And it looks like a good place to look is the folder;

"react-native/Libraries/Types"

In any other case, jump into the source code and follow from the component you're trying to find the event for. Usually it's pretty straightforward, although annoying, to find the type.