Type Animated.event listener argument (#50390)

Summary:
Pull Request resolved: #50390

Changelog: [Internal]

Reviewed By: huntie

Differential Revision: D72151986

fbshipit-source-id: 26c9b6dff669fac6fcb8db1f6a0b23648f6f4afb

Author: j-piasecki

packages/react-native/Libraries/Animated/AnimatedEvent.js

@@ -10,6 +10,7 @@
 
 'use strict';
 
+import type {NativeSyntheticEvent} from '../Types/CoreEventTypes';
 import type {PlatformConfig} from './AnimatedPlatformConfig';
 
 import NativeAnimatedHelper from '../../src/private/animated/NativeAnimatedHelper';
@@ -22,8 +23,8 @@ export type Mapping =
   | {[key: string]: Mapping, ...}
   | AnimatedValue
   | AnimatedValueXY;
-export type EventConfig = {
-  listener?: ?Function,
+export type EventConfig<T> = {
+  listener?: ?(NativeSyntheticEvent<T>) => mixed,
   useNativeDriver: boolean,
   platformConfig?: PlatformConfig,
 };
@@ -150,7 +151,7 @@ export class AnimatedEvent {
   __isNative: boolean;
   __platformConfig: ?PlatformConfig;
 
-  constructor(argMapping: $ReadOnlyArray<?Mapping>, config: EventConfig) {
+  constructor(argMapping: $ReadOnlyArray<?Mapping>, config: EventConfig<any>) {
     this._argMapping = argMapping;
 
     if (config == null) {

packages/react-native/Libraries/Animated/AnimatedImplementation.js

@@ -540,9 +540,9 @@ function unforkEvent(
   }
 }
 
-const event = function (
+const event = function <T>(
   argMapping: $ReadOnlyArray<?Mapping>,
-  config: EventConfig,
+  config: EventConfig<T>,
 ): any {
   const animatedEvent = new AnimatedEvent(argMapping, config);
   if (animatedEvent.__isNative) {

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -128,8 +128,8 @@ exports[`public API should not change unintentionally Libraries/Animated/Animate
   | { [key: string]: Mapping, ... }
   | AnimatedValue
   | AnimatedValueXY;
-export type EventConfig = {
-  listener?: ?Function,
+export type EventConfig<T> = {
+  listener?: ?(NativeSyntheticEvent<T>) => mixed,
   useNativeDriver: boolean,
   platformConfig?: PlatformConfig,
 };
@@ -140,7 +140,10 @@ declare export function attachNativeEvent(
   platformConfig: ?PlatformConfig
 ): { detach: () => void };
 declare export class AnimatedEvent {
-  constructor(argMapping: $ReadOnlyArray<?Mapping>, config: EventConfig): void;
+  constructor(
+    argMapping: $ReadOnlyArray<?Mapping>,
+    config: EventConfig<any>
+  ): void;
 }
 "
 `;
@@ -278,9 +281,9 @@ declare function unforkEvent(
   event: ?AnimatedEvent | ?Function,
   listener: Function
 ): void;
-declare const event: (
+declare const event: <T>(
   argMapping: $ReadOnlyArray<?Mapping>,
-  config: EventConfig
+  config: EventConfig<T>
 ) => any;
 type AnimatedNumeric =
   | AnimatedAddition
@@ -9655,6 +9658,7 @@ export type {
   MouseEvent,
   NativeMouseEvent,
   NativePointerEvent,
+  NativeScrollEvent,
   NativeSyntheticEvent,
   NativeTouchEvent,
   NativeUIEvent,

packages/react-native/index.js.flow

@@ -389,6 +389,7 @@ export type {
   MouseEvent,
   NativeMouseEvent,
   NativePointerEvent,
+  NativeScrollEvent,
   NativeSyntheticEvent,
   NativeTouchEvent,
   NativeUIEvent,

packages/react-native/src/private/animated/NativeAnimatedHelper.js

@@ -384,7 +384,7 @@ function assertNativeAnimatedModule(): void {
 let _warnedMissingNativeAnimated = false;
 
 function shouldUseNativeDriver(
-  config: $ReadOnly<{...AnimationConfig, ...}> | EventConfig,
+  config: $ReadOnly<{...AnimationConfig, ...}> | EventConfig<mixed>,
 ): boolean {
   if (config.useNativeDriver == null) {
     console.warn(