Transform mixed to unknown in xplat/js (#54954)

Summary:
Pull Request resolved: #54954

We are transforming the following utility types to be more consistent with typescript and better AI integration:

* `$NonMaybeType` -> `NonNullable`
* `$ReadOnly` -> `Readonly`
* `$ReadOnlyArray` -> `ReadonlyArray`
* `$ReadOnlyMap` -> `ReadonlyMap`
* `$ReadOnlySet` -> `ReadonlySet`
* `$Keys` -> `keyof`
* `$Values` -> `Values`
* `mixed` -> `unknown`

See details in https://fb.workplace.com/groups/flowlang/permalink/1837907750148213/.
drop-conflicts

Reviewed By: SamChou19815

Differential Revision: D89581744

fbshipit-source-id: 58a6c246629bbe4fb5c0af447dc002c48e10c342

Author: marcoww6

packages/react-native-codegen/src/generators/Utils.js

@@ -23,7 +23,7 @@ function indent(nice: string, spaces: number): string {
       if (line.length === 0 || index === 0) {
         return line;
       }
-      const emptySpaces = new Array<mixed>(spaces + 1).join(' ');
+      const emptySpaces = new Array<unknown>(spaces + 1).join(' ');
       return emptySpaces + line;
     })
     .join('\n');

packages/react-native-codegen/src/parsers/flow/components/commands.js

@@ -131,7 +131,7 @@ function buildCommandSchema(
         };
         break;
       default:
-        (type: mixed);
+        (type: unknown);
         throw new Error(
           `Unsupported param type for method "${name}", param "${paramName}". Found ${type}`,
         );
@@ -160,7 +160,7 @@ function buildCommandSchema(
 type Allowed = ComponentCommandArrayTypeAnnotation['elementType'];
 
 function getCommandArrayElementTypeType(
-  inputType: mixed,
+  inputType: unknown,
   parser: Parser,
 ): Allowed {
   // TODO: T172453752 support more complex type annotation for array element

packages/react-native-codegen/src/parsers/typescript/components/commands.js

@@ -102,7 +102,7 @@ function buildCommandSchemaInternal(
         };
         break;
       default:
-        (type: mixed);
+        (type: unknown);
         throw new Error(
           `Unsupported param type for method "${name}", param "${paramName}". Found ${type}`,
         );
@@ -129,7 +129,7 @@ function buildCommandSchemaInternal(
 }
 
 function getCommandArrayElementTypeType(
-  inputType: mixed,
+  inputType: unknown,
   parser: Parser,
 ): ComponentCommandArrayTypeAnnotation['elementType'] {
   // TODO: T172453752 support more complex type annotation for array element

packages/react-native-codegen/src/parsers/typescript/components/componentsUtils.js

@@ -335,7 +335,7 @@ function getTypeAnnotationForArray<T>(
         type: 'FloatTypeAnnotation',
       };
     default:
-      (type: mixed);
+      (type: unknown);
       throw new Error(`Unknown prop type for "${name}": ${type}`);
   }
 }

packages/react-native-compatibility-check/src/__tests__/__fixtures__/native-component-with-props-all-types/NativeComponent.js.flow

@@ -28,7 +28,7 @@ export type Props = $ReadOnly<{
   int: Int32,
   stringUnion: WithDefault<'foo' | 'bar', 'bar'>,
   intUnion: WithDefault<1 | 2, 1>,
-  mixed: mixed,
+  mixed: unknown,
 
   backgroundColor?: WithDefault<string, 'transparent'>,
   height?: WithDefault<Int32, 100>,

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

@@ -88,47 +88,47 @@ export type PressabilityConfig = $ReadOnly<{
   /**
    * Called after the element loses focus.
    */
-  onBlur?: ?(event: BlurEvent) => mixed,
+  onBlur?: ?(event: BlurEvent) => unknown,
 
   /**
    * Called after the element is focused.
    */
-  onFocus?: ?(event: FocusEvent) => mixed,
+  onFocus?: ?(event: FocusEvent) => unknown,
 
   /**
    * Called when the hover is activated to provide visual feedback.
    */
-  onHoverIn?: ?(event: MouseEvent) => mixed,
+  onHoverIn?: ?(event: MouseEvent) => unknown,
 
   /**
    * Called when the hover is deactivated to undo visual feedback.
    */
-  onHoverOut?: ?(event: MouseEvent) => mixed,
+  onHoverOut?: ?(event: MouseEvent) => unknown,
 
   /**
    * Called when a long press gesture has been triggered.
    */
-  onLongPress?: ?(event: GestureResponderEvent) => mixed,
+  onLongPress?: ?(event: GestureResponderEvent) => unknown,
 
   /**
    * Called when a press gesture has been triggered.
    */
-  onPress?: ?(event: GestureResponderEvent) => mixed,
+  onPress?: ?(event: GestureResponderEvent) => unknown,
 
   /**
    * Called when the press is activated to provide visual feedback.
    */
-  onPressIn?: ?(event: GestureResponderEvent) => mixed,
+  onPressIn?: ?(event: GestureResponderEvent) => unknown,
 
   /**
    * Called when the press location moves. (This should rarely be used.)
    */
-  onPressMove?: ?(event: GestureResponderEvent) => mixed,
+  onPressMove?: ?(event: GestureResponderEvent) => unknown,
 
   /**
    * Called when the press is deactivated to undo visual feedback.
    */
-  onPressOut?: ?(event: GestureResponderEvent) => mixed,
+  onPressOut?: ?(event: GestureResponderEvent) => unknown,
 
   /**
    * Whether to prevent any other native components from becoming responder

packages/react-native/Libraries/Pressability/__tests__/Pressability-test.js

@@ -26,7 +26,7 @@ const itif = (condition: boolean) => {
 };
 
 // TODO: Move this util to a shared location.
-function getMock<TArguments: $ReadOnlyArray<mixed>, TReturn>(
+function getMock<TArguments: $ReadOnlyArray<unknown>, TReturn>(
   fn: (...args: TArguments) => TReturn,
 ): JestMockFn<TArguments, TReturn> {
   if (!jest.isMockFunction(fn)) {

packages/react-native/Libraries/ReactNative/AppRegistry.flow.js

@@ -29,7 +29,7 @@ export type AppConfig = {
   ...
 };
 export type AppParameters = {
-  initialProps: $ReadOnly<{[string]: mixed, ...}>,
+  initialProps: $ReadOnly<{[string]: unknown, ...}>,
   rootTag: RootTag,
   fabric?: boolean,
 };

packages/react-native/Libraries/ReactNative/BridgelessUIManager.js

@@ -265,7 +265,7 @@ const UIManagerJS: UIManagerJSInterface & {[string]: any} = {
   ...UIManagerJSDeprecatedPlatformAPIs,
   ...UIManagerJSPlatformAPIs,
   ...UIManagerJSUnusedInNewArchAPIs,
-  getViewManagerConfig: (viewManagerName: string): mixed => {
+  getViewManagerConfig: (viewManagerName: string): unknown => {
     if (getUIManagerConstants) {
       const constants = getUIManagerConstantsCached();
       if (

packages/react-native/Libraries/ReactNative/FabricUIManager.js

@@ -71,7 +71,7 @@ export interface Spec {
   +dispatchCommand: (
     node: Node,
     commandName: string,
-    args: Array<mixed>,
+    args: Array<unknown>,
   ) => void;
   +findNodeAtPoint: (
     node: Node,