react · rubennorte · Jul 29, 2026 · Jul 29, 2026 · Jul 29, 2026 · Jul 29, 2026
diff --git a/packages/react-native/Libraries/ActionSheetIOS/ActionSheetIOS.js b/packages/react-native/Libraries/ActionSheetIOS/ActionSheetIOS.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
@@ -49,6 +49,7 @@ export type ShareActionSheetIOSOptions = Readonly<{
 export type ShareActionSheetError = Readonly<{
   domain: string,
   code: string,
+  // $FlowFixMe[unclear-type]
   userInfo?: ?Object,
   message: string,
 }>;
@@ -155,7 +156,9 @@ const ActionSheetIOS = {
    */
   showShareActionSheetWithOptions(
     options: ShareActionSheetIOSOptions,
+    // $FlowFixMe[unclear-type]
     failureCallback: Function | ((error: ShareActionSheetError) => void),
+    // $FlowFixMe[unclear-type]
     successCallback: Function | ((success: boolean, method: ?string) => void),
   ) {
     invariant(

diff --git a/packages/react-native/Libraries/Alert/Alert.js b/packages/react-native/Libraries/Alert/Alert.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
@@ -26,6 +26,7 @@ export type AlertButtonStyle = 'default' | 'cancel' | 'destructive';
 
 export type AlertButton = {
   text?: string,
+  // $FlowFixMe[unclear-type]
   onPress?: ?((value?: string) => any) | ?Function,
   isPreferred?: boolean,
   style?: AlertButtonStyle,
@@ -121,6 +122,7 @@ class Alert {
         cancelable: false,
       };
 
+      // $FlowFixMe[sketchy-null-bool]
       if (options && options.cancelable) {
         config.cancelable = options.cancelable;
       }
@@ -141,6 +143,7 @@ class Alert {
         config.buttonNegative = buttonNegative.text || '';
       }
       if (buttonPositive) {
+        // $FlowFixMe[sketchy-null-string]
         config.buttonPositive = buttonPositive.text || defaultPositiveText;
       }
 
@@ -186,6 +189,7 @@ class Alert {
     options?: AlertOptions,
   ): void {
     if (Platform.OS === 'ios') {
+      // $FlowFixMe[unclear-type]
       let callbacks: Array<?any> = [];
       const buttons = [];
       let cancelButtonKey;
@@ -201,9 +205,11 @@ class Alert {
           } else if (btn.style === 'destructive') {
             destructiveButtonKey = String(index);
           }
+          // $FlowFixMe[sketchy-null-bool]
           if (btn.isPreferred) {
             preferredButtonKey = String(index);
           }
+          // $FlowFixMe[sketchy-null-string]
           if (btn.text || index < (callbackOrButtons || []).length - 1) {
             const btnDef: {[number]: string} = {};
             btnDef[index] = btn.text || '';
@@ -215,6 +221,7 @@ class Alert {
       alertWithArgs(
         {
           title: title || '',
+          // $FlowFixMe[sketchy-null-string]
           message: message || undefined,
           buttons,
           type: type || undefined,

diff --git a/packages/react-native/Libraries/Blob/File.js b/packages/react-native/Libraries/Blob/File.js
@@ -4,10 +4,12 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
+// flowlint unsafe-getters-setters:off
+
 'use strict';
 
 import type {BlobOptions} from './BlobTypes';

diff --git a/packages/react-native/Libraries/Blob/FileReader.js b/packages/react-native/Libraries/Blob/FileReader.js
@@ -4,10 +4,12 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
+// flowlint unsafe-getters-setters:off
+
 import type {EventCallback} from '../../src/private/webapis/dom/events/EventTarget';
 import type Blob from './Blob';
 

diff --git a/packages/react-native/Libraries/Blob/URL.js b/packages/react-native/Libraries/Blob/URL.js
@@ -4,10 +4,12 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
+// flowlint unsafe-getters-setters:off
+
 import type Blob from './Blob';
 
 import NativeBlobModule from './NativeBlobModule';
@@ -79,6 +81,7 @@ export class URL {
   // $FlowFixMe[missing-local-annot]
   constructor(url: string, base?: string | URL) {
     let baseUrl = null;
+    // $FlowFixMe[sketchy-null-string]
     if (!base || validateBaseUrl(url)) {
       this._url = url;
       if (this._url.includes('#')) {
@@ -112,13 +115,14 @@ export class URL {
       if (baseUrl.endsWith('/')) {
         baseUrl = baseUrl.slice(0, baseUrl.length - 1);
       }
-      if (!url.startsWith('/')) {
-        url = `/${url}`;
+      let path = url;
+      if (!path.startsWith('/')) {
+        path = `/${path}`;
       }
-      if (baseUrl.endsWith(url)) {
-        url = '';
+      if (baseUrl.endsWith(path)) {
+        path = '';
       }
-      this._url = `${baseUrl}${url}`;
+      this._url = `${baseUrl}${path}`;
     }
   }
 

diff --git a/packages/react-native/Libraries/Blob/URLSearchParams.js b/packages/react-native/Libraries/Blob/URLSearchParams.js
@@ -4,10 +4,12 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
+// flowlint unsafe-getters-setters:off
+
 // Small subset from whatwg-url: https://github.com/jsdom/whatwg-url/tree/master/src
 // The reference code bloat comes from Unicode issues with URLs, so those won't work here.
 export class URLSearchParams {

diff --git a/packages/react-native/Libraries/Blob/URLSearchParams.js.flow b/packages/react-native/Libraries/Blob/URLSearchParams.js.flow
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 

diff --git a/packages/react-native/Libraries/Components/ActivityIndicator/ActivityIndicator.js b/packages/react-native/Libraries/Components/ActivityIndicator/ActivityIndicator.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
@@ -115,7 +115,7 @@ const ActivityIndicator: component(
   style,
   ...restProps
 }: {
-  ref?: any,
+  ref?: React.RefSetter<ActivityIndicatorInstance>,
   ...ActivityIndicatorProps,
 }) => {
   let sizeStyle;

diff --git a/packages/react-native/Libraries/Components/Button.js b/packages/react-native/Libraries/Components/Button.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
@@ -232,7 +232,7 @@ const Button: component(
   } = props;
   const buttonStyles: Array<ViewStyleProp> = [styles.button];
   const textStyles: Array<TextStyleProp> = [styles.text];
-  if (color) {
+  if (Boolean(color)) {
     if (Platform.OS === 'ios') {
       textStyles.push({color: color});
     } else {
@@ -256,7 +256,7 @@ const Button: component(
       ? {..._accessibilityState, disabled}
       : _accessibilityState;
 
-  if (disabled) {
+  if (disabled === true) {
     buttonStyles.push(styles.buttonDisabled);
     textStyles.push(styles.textDisabled);
   }
@@ -279,7 +279,10 @@ const Button: component(
       accessible={accessible}
       accessibilityActions={accessibilityActions}
       onAccessibilityAction={onAccessibilityAction}
-      accessibilityLabel={ariaLabel || accessibilityLabel}
+      accessibilityLabel={
+        // $FlowFixMe[sketchy-null-string]
+        ariaLabel || accessibilityLabel
+      }
       accessibilityHint={accessibilityHint}
       accessibilityLanguage={accessibilityLanguage}
       accessibilityRole="button"

diff --git a/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.android.js b/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.android.js
@@ -4,10 +4,12 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
+// flowlint unsafe-getters-setters:off
+
 import type {
   MeasureInWindowOnSuccessCallback,
   MeasureLayoutOnSuccessCallback,
@@ -204,7 +206,7 @@ class DrawerLayoutAndroid
     );
   }
 
-  setNativeProps(nativeProps: Object) {
+  setNativeProps(nativeProps: {...}) {
     nullthrows(this._nativeRef.current).setNativeProps(nativeProps);
   }
 }

diff --git a/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.js b/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 

diff --git a/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroidTypes.js b/packages/react-native/Libraries/Components/DrawerAndroid/DrawerLayoutAndroidTypes.js
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
+ * @flow strict-local
  * @format
  */
 
@@ -127,7 +127,7 @@ export interface DrawerLayoutAndroidMethods {
     onSuccess: MeasureLayoutOnSuccessCallback,
     onFail?: () => void,
   ): void;
-  setNativeProps(nativeProps: Object): void;
+  setNativeProps(nativeProps: {...}): void;
 }
 
 export type DrawerLayoutAndroidInstance = DrawerLayoutAndroidMethods;