Add flow definitions for Alert and align them with TypeScript (#49006)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49006

Changelog: [Internal]

Reviewed By: huntie

Differential Revision: D68774525

fbshipit-source-id: 509f26b0f5f0d309502681f3228ae519689d480a

packages/react-native/Libraries/Alert/Alert.flow.js

@@ -0,0 +1,62 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+export type AlertType =
+  | 'default'
+  | 'plain-text'
+  | 'secure-text'
+  | 'login-password';
+
+export type AlertButtonStyle = 'default' | 'cancel' | 'destructive';
+
+export type AlertButton = {
+  text?: string,
+  onPress?: ?((value?: string) => any) | ?Function,
+  isPreferred?: boolean,
+  style?: AlertButtonStyle,
+  ...
+};
+
+export type Buttons = Array<AlertButton>;
+
+export type AlertOptions = {
+  /** @platform android */
+  cancelable?: ?boolean,
+  userInterfaceStyle?: 'unspecified' | 'light' | 'dark',
+  /** @platform android */
+  onDismiss?: ?() => void,
+  ...
+};
+
+/**
+ * Launches an alert dialog with the specified title and message.
+ *
+ * See https://reactnative.dev/docs/alert
+ */
+declare class Alert {
+  static alert(
+    title: ?string,
+    message?: ?string,
+    buttons?: Buttons,
+    options?: AlertOptions,
+  ): void;
+
+  static prompt(
+    title: ?string,
+    message?: ?string,
+    callbackOrButtons?: ?(((text: string) => void) | Buttons),
+    type?: ?AlertType,
+    defaultValue?: string,
+    keyboardType?: string,
+    options?: AlertOptions,
+  ): void;
+}
+
+export default Alert;

packages/react-native/Libraries/Alert/Alert.js

@@ -9,45 +9,19 @@
  */
 
 import type {DialogOptions} from '../NativeModules/specs/NativeDialogManagerAndroid';
+import type {AlertOptions, AlertType, Buttons} from './Alert.flow';
 
 import Platform from '../Utilities/Platform';
 import RCTAlertManager from './RCTAlertManager';
 
-export type AlertType =
-  | 'default'
-  | 'plain-text'
-  | 'secure-text'
-  | 'login-password';
-export type AlertButtonStyle = 'default' | 'cancel' | 'destructive';
-export type AlertButton = {
-  text?: string,
-  onPress?: ?Function,
-  isPreferred?: boolean,
-  style?: AlertButtonStyle,
-  ...
-};
-export type Buttons = Array<AlertButton>;
+export type * from './Alert.flow';
 
-type Options = {
-  /** @platform android */
-  cancelable?: ?boolean,
-  userInterfaceStyle?: 'unspecified' | 'light' | 'dark',
-  /** @platform android */
-  onDismiss?: ?() => void,
-  ...
-};
-
-/**
- * Launches an alert dialog with the specified title and message.
- *
- * See https://reactnative.dev/docs/alert
- */
 class Alert {
   static alert(
     title: ?string,
     message?: ?string,
     buttons?: Buttons,
-    options?: Options,
+    options?: AlertOptions,
   ): void {
     if (Platform.OS === 'ios') {
       Alert.prompt(
@@ -126,7 +100,7 @@ class Alert {
     type?: ?AlertType = 'plain-text',
     defaultValue?: string,
     keyboardType?: string,
-    options?: Options,
+    options?: AlertOptions,
   ): void {
     if (Platform.OS === 'ios') {
       let callbacks: Array<?any> = [];

packages/react-native/Libraries/Alert/RCTAlertManager.flow.js

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ */
+
+import type {Args} from './NativeAlertManager';
+
+declare const RCTAlertManager: {
+  alertWithArgs(
+    args: Args,
+    callback: (id: number, value: string) => void,
+  ): void,
+};
+
+export default RCTAlertManager;

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

@@ -35,7 +35,7 @@ declare export default typeof NativeActionSheetManager;
 "
 `;
 
-exports[`public API should not change unintentionally Libraries/Alert/Alert.js 1`] = `
+exports[`public API should not change unintentionally Libraries/Alert/Alert.flow.js 1`] = `
 "export type AlertType =
   | \\"default\\"
   | \\"plain-text\\"
@@ -44,13 +44,13 @@ exports[`public API should not change unintentionally Libraries/Alert/Alert.js 1
 export type AlertButtonStyle = \\"default\\" | \\"cancel\\" | \\"destructive\\";
 export type AlertButton = {
   text?: string,
-  onPress?: ?Function,
+  onPress?: ?((value?: string) => any) | ?Function,
   isPreferred?: boolean,
   style?: AlertButtonStyle,
   ...
 };
 export type Buttons = Array<AlertButton>;
-type Options = {
+export type AlertOptions = {
   cancelable?: ?boolean,
   userInterfaceStyle?: \\"unspecified\\" | \\"light\\" | \\"dark\\",
   onDismiss?: ?() => void,
@@ -61,7 +61,7 @@ declare class Alert {
     title: ?string,
     message?: ?string,
     buttons?: Buttons,
-    options?: Options
+    options?: AlertOptions
   ): void;
   static prompt(
     title: ?string,
@@ -70,7 +70,30 @@ declare class Alert {
     type?: ?AlertType,
     defaultValue?: string,
     keyboardType?: string,
-    options?: Options
+    options?: AlertOptions
+  ): void;
+}
+declare export default typeof Alert;
+"
+`;
+
+exports[`public API should not change unintentionally Libraries/Alert/Alert.js 1`] = `
+"export type * from \\"./Alert.flow\\";
+declare class Alert {
+  static alert(
+    title: ?string,
+    message?: ?string,
+    buttons?: Buttons,
+    options?: AlertOptions
+  ): void;
+  static prompt(
+    title: ?string,
+    message?: ?string,
+    callbackOrButtons?: ?(((text: string) => void) | Buttons),
+    type?: ?AlertType,
+    defaultValue?: string,
+    keyboardType?: string,
+    options?: AlertOptions
   ): void;
 }
 declare export default typeof Alert;
@@ -83,6 +106,17 @@ declare export default typeof NativeAlertManager;
 "
 `;
 
+exports[`public API should not change unintentionally Libraries/Alert/RCTAlertManager.flow.js 1`] = `
+"declare const RCTAlertManager: {
+  alertWithArgs(
+    args: Args,
+    callback: (id: number, value: string) => void
+  ): void,
+};
+declare export default typeof RCTAlertManager;
+"
+`;
+
 exports[`public API should not change unintentionally Libraries/Alert/RCTAlertManager.js.flow 1`] = `
 "declare export default {
   alertWithArgs(