diff --git a/packages/react-native/scripts/bundle.js b/packages/react-native/scripts/bundle.js
index ec2b42b2b1b..5a9e7035a59 100644
--- a/packages/react-native/scripts/bundle.js
+++ b/packages/react-native/scripts/bundle.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -16,6 +17,7 @@ const {readFileSync} = require('fs');
 const path = require('path');
 
 // Commander 12.0.0 changes from the global to named export
+// $FlowFixMe[signature-verification-failure]
 const program = commander.program ?? commander;
 
 program.version(
@@ -37,7 +39,14 @@ program
   .allowUnknownOption()
   .action(async function handleAction() {
     let config = null;
-    let options = program.opts();
+    let options = program
+      .opts /*::<{
+      configCmd?: string,
+      loadConfig?: string,
+      verbose: boolean,
+      ...
+    }>*/
+      ();
     if (options.loadConfig != null) {
       config = JSON.parse(
         options.loadConfig.replace(/^\W*'/, '').replace(/'\W*$/, ''),
diff --git a/packages/react-native/scripts/codegen/__fixtures__/fixtures.js b/packages/react-native/scripts/codegen/__fixtures__/fixtures.js
index 472242abe9b..61166c9abb1 100644
--- a/packages/react-native/scripts/codegen/__fixtures__/fixtures.js
+++ b/packages/react-native/scripts/codegen/__fixtures__/fixtures.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -120,6 +121,7 @@ const SCHEMA_TEXT = `
 }
 `;
 
+// $FlowFixMe[signature-verification-failure]
 const SCHEMA = JSON.parse(SCHEMA_TEXT);
 
 module.exports = {
diff --git a/packages/react-native/scripts/codegen/__tests__/generate-artifacts-executor-test.js b/packages/react-native/scripts/codegen/__tests__/generate-artifacts-executor-test.js
index 01953bacd8e..5e5150b33f5 100644
--- a/packages/react-native/scripts/codegen/__tests__/generate-artifacts-executor-test.js
+++ b/packages/react-native/scripts/codegen/__tests__/generate-artifacts-executor-test.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -243,7 +244,7 @@ describe('delete empty files and folders', () => {
 
   it("when path is folder and it's empty, removes it", () => {
     const targetFolder = 'build';
-    const content = [];
+    const content = [] as Array<string>;
 
     let statSyncInvocationCount = 0;
     let readdirInvocationCount = 0;
@@ -290,8 +291,8 @@ describe('delete empty files and folders', () => {
       path.normalize('build/notEmptyFile'),
     ];
 
-    const emptyContent = [];
-    let fileSizes = {};
+    const emptyContent = [] as Array<string>;
+    let fileSizes = {} as {[string]: number};
     fileSizes[path.normalize('build/emptyFile')] = 0;
     fileSizes[path.normalize('build/notEmptyFile')] = 32;
 
@@ -344,7 +345,7 @@ describe('delete empty files and folders', () => {
   it('when path is folder and it contains only empty folders, removes everything', () => {
     const targetFolder = 'build';
     const content = ['emptyFolder1', 'emptyFolder2'];
-    const emptyContent = [];
+    const emptyContent = [] as Array<string>;
 
     let statSyncInvocation = [];
     let rmSyncInvocation = [];
diff --git a/packages/react-native/scripts/codegen/__tests__/generate-specs-cli-executor-test.js b/packages/react-native/scripts/codegen/__tests__/generate-specs-cli-executor-test.js
index f3c74200f43..d0ec7ab82dd 100644
--- a/packages/react-native/scripts/codegen/__tests__/generate-specs-cli-executor-test.js
+++ b/packages/react-native/scripts/codegen/__tests__/generate-specs-cli-executor-test.js
@@ -4,6 +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 strict-local
  * @format
  */
 
diff --git a/packages/react-native/scripts/codegen/codegen-utils.js b/packages/react-native/scripts/codegen/codegen-utils.js
index d151bda6eff..4c03007bce3 100644
--- a/packages/react-native/scripts/codegen/codegen-utils.js
+++ b/packages/react-native/scripts/codegen/codegen-utils.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -19,11 +20,13 @@
  *
  * @return an object that can generate the code for the New Architecture.
  */
-function getCodegen() {
+function getCodegen() /*: $FlowFixMe */ {
   let RNCodegen;
   try {
+    // $FlowIgnore[cannot-resolve-module]
     RNCodegen = require('../../packages/react-native-codegen/lib/generators/RNCodegen.js');
   } catch (e) {
+    // $FlowIgnore[cannot-resolve-module]
     RNCodegen = require('@react-native/codegen/lib/generators/RNCodegen.js');
   }
   if (!RNCodegen) {
@@ -32,11 +35,13 @@ function getCodegen() {
   return RNCodegen;
 }
 
-function getCombineJSToSchema() {
+function getCombineJSToSchema() /*: $FlowFixMe */ {
   let combineJSToSchema;
   try {
+    // $FlowIgnore[cannot-resolve-module]
     combineJSToSchema = require('../../packages/react-native-codegen/lib/cli/combine/combine-js-to-schema.js');
   } catch (e) {
+    // $FlowIgnore[cannot-resolve-module]
     combineJSToSchema = require('@react-native/codegen/lib/cli/combine/combine-js-to-schema.js');
   }
   if (!combineJSToSchema) {
@@ -46,6 +51,6 @@ function getCombineJSToSchema() {
 }
 
 module.exports = {
-  getCodegen: getCodegen,
-  getCombineJSToSchema: getCombineJSToSchema,
+  getCodegen,
+  getCombineJSToSchema,
 };
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/constants.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/constants.js
index 6f828737daa..9a8b7c4a6dc 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/constants.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/constants.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -21,11 +22,19 @@ const REACT_NATIVE_REPOSITORY_ROOT = path.join(
   '..',
 );
 
-const REACT_NATIVE_PACKAGE_ROOT_FOLDER = path.join(__dirname, '..', '..', '..');
+const REACT_NATIVE_PACKAGE_ROOT_FOLDER = path.join(
+    __dirname,
+    '..',
+    '..',
+    '..',
+  ) /*:: as string */;
 const CODEGEN_REPO_PATH = `${REACT_NATIVE_REPOSITORY_ROOT}/packages/react-native-codegen`;
 
 const RNCORE_CONFIGS = {
-  ios: path.join(REACT_NATIVE_PACKAGE_ROOT_FOLDER, 'ReactCommon'),
+  ios: path.join(
+    REACT_NATIVE_PACKAGE_ROOT_FOLDER,
+    'ReactCommon',
+  ) /*:: as string */,
   android: path.join(
     REACT_NATIVE_PACKAGE_ROOT_FOLDER,
     'ReactAndroid',
@@ -33,42 +42,43 @@ const RNCORE_CONFIGS = {
     'generated',
     'source',
     'codegen',
-  ),
+  ) /*:: as string */,
 };
 
 const CORE_LIBRARIES_WITH_OUTPUT_FOLDER = {
-  rncore: RNCORE_CONFIGS,
-  FBReactNativeSpec: {
-    ios: path.join(
-      REACT_NATIVE_PACKAGE_ROOT_FOLDER,
-      'React',
-      'FBReactNativeSpec',
-    ),
-    android: path.join(
-      REACT_NATIVE_PACKAGE_ROOT_FOLDER,
-      'ReactAndroid',
-      'build',
-      'generated',
-      'source',
-      'codegen',
-    ),
-  },
-};
+    rncore: RNCORE_CONFIGS,
+    FBReactNativeSpec: {
+      ios: path.join(
+        REACT_NATIVE_PACKAGE_ROOT_FOLDER,
+        'React',
+        'FBReactNativeSpec',
+      ) /*:: as string */,
+      android: path.join(
+        REACT_NATIVE_PACKAGE_ROOT_FOLDER,
+        'ReactAndroid',
+        'build',
+        'generated',
+        'source',
+        'codegen',
+      ) /*:: as string */,
+    },
+  } /*:: as {[string]: $FlowFixMe} */;
 
 const packageJsonPath = path.join(
   REACT_NATIVE_PACKAGE_ROOT_FOLDER,
   'package.json',
 );
 
-const packageJson = JSON.parse(fs.readFileSync(packageJsonPath));
+// $FlowFixMe[signature-verification-failure]
+const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, 'utf8'));
 const REACT_NATIVE = packageJson.name;
 
 const TEMPLATES_FOLDER_PATH = path.join(
-  REACT_NATIVE_PACKAGE_ROOT_FOLDER,
-  'scripts',
-  'codegen',
-  'templates',
-);
+    REACT_NATIVE_PACKAGE_ROOT_FOLDER,
+    'scripts',
+    'codegen',
+    'templates',
+  ) /*:: as string */;
 
 module.exports = {
   CODEGEN_REPO_PATH,
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateAppDependencyProvider.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateAppDependencyProvider.js
index 8e3e60615ad..bf1a24b4732 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateAppDependencyProvider.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateAppDependencyProvider.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -28,7 +29,7 @@ const APP_DEPENDENCY_PROVIDER_PODSPEC_TEMPLATE_PATH = path.join(
   'ReactAppDependencyProvider.podspec.template',
 );
 
-function generateAppDependencyProvider(outputDir) {
+function generateAppDependencyProvider(outputDir /*: string */) {
   fs.mkdirSync(outputDir, {recursive: true});
   codegenLog('Generating RCTAppDependencyProvider');
 
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateCustomURLHandlers.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateCustomURLHandlers.js
index ed5c2696fb7..85e1b3e7e06 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateCustomURLHandlers.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateCustomURLHandlers.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -23,13 +24,17 @@ const MODULES_PROTOCOLS_MM_TEMPLATE_PATH = path.join(
   'RCTModulesConformingToProtocolsProviderMM.template',
 );
 
-function generateCustomURLHandlers(libraries, outputDir) {
+function generateCustomURLHandlers(
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+  outputDir /*: string */,
+) {
   const iosAnnotations = parseiOSAnnotations(libraries);
 
-  const imageURLLoaderModules = new Set();
-  const imageDataDecoderModules = new Set();
-  const urlRequestHandlersModules = new Set();
+  const imageURLLoaderModules = new Set /*::<string>*/();
+  const imageDataDecoderModules = new Set /*::<string>*/();
+  const urlRequestHandlersModules = new Set /*::<string>*/();
 
+  // $FlowFixMe[missing-local-annot]]
   const wrapInArrayIfNecessary = value =>
     Array.isArray(value) || value == null ? value : [value];
   // Old API
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateFBReactNativeSpecIOS.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateFBReactNativeSpecIOS.js
index 9b029c58943..70ceacf800c 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateFBReactNativeSpecIOS.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateFBReactNativeSpecIOS.js
@@ -4,6 +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 strict-local
  * @format
  */
 
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateNativeCode.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateNativeCode.js
index f505a32c185..daba7206e4f 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateNativeCode.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateNativeCode.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -17,17 +18,22 @@ const os = require('os');
 const path = require('path');
 
 function generateNativeCode(
-  outputPath,
-  schemaInfos,
-  includesGeneratedCode,
-  platform,
-) {
+  outputPath /*: string */,
+  schemaInfos /*: $ReadOnlyArray<$FlowFixMe> */,
+  includesGeneratedCode /*: boolean */,
+  platform /*: string */,
+) /*: Array<void> */ {
   return schemaInfos.map(schemaInfo => {
     generateCode(outputPath, schemaInfo, includesGeneratedCode, platform);
   });
 }
 
-function generateCode(outputPath, schemaInfo, includesGeneratedCode, platform) {
+function generateCode(
+  outputPath /*: string */,
+  schemaInfo /*: $FlowFixMe */,
+  includesGeneratedCode /*: boolean */,
+  platform /*: string */,
+) {
   if (shouldSkipGenerationForRncore(schemaInfo, platform)) {
     codegenLog(
       '[Codegen - rncore] Skipping iOS code generation for rncore as it has been generated already.',
@@ -65,11 +71,15 @@ function generateCode(outputPath, schemaInfo, includesGeneratedCode, platform) {
   const outputDir =
     reactNativeCoreLibraryOutputPath(libraryName, platform) ?? outputPath;
   fs.mkdirSync(outputDir, {recursive: true});
+  // $FlowIssue[prop-missing] - `fs.cpSync` is missing in Flow libdefs.
   fs.cpSync(tmpOutputDir, outputDir, {recursive: true});
   codegenLog(`Generated artifacts: ${outputDir}`);
 }
 
-function shouldSkipGenerationForRncore(schemaInfo, platform) {
+function shouldSkipGenerationForRncore(
+  schemaInfo /*: $FlowFixMe */,
+  platform /*: string */,
+) {
   if (platform !== 'ios' || schemaInfo.library.config.name !== 'rncore') {
     return false;
   }
@@ -82,13 +92,19 @@ function shouldSkipGenerationForRncore(schemaInfo, platform) {
   );
 }
 
-function reactNativeCoreLibraryOutputPath(libraryName, platform) {
+function reactNativeCoreLibraryOutputPath(
+  libraryName /*: string */,
+  platform /*: string */,
+) {
   return CORE_LIBRARIES_WITH_OUTPUT_FOLDER[libraryName]
     ? CORE_LIBRARIES_WITH_OUTPUT_FOLDER[libraryName][platform]
     : null;
 }
 
-function shouldSkipGenerationForFBReactNativeSpec(schemaInfo, platform) {
+function shouldSkipGenerationForFBReactNativeSpec(
+  schemaInfo /*: $FlowFixMe */,
+  platform /*: string */,
+) {
   if (
     platform !== 'ios' ||
     schemaInfo.library.config.name !== 'FBReactNativeSpec'
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTModuleProviders.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTModuleProviders.js
index a9d484f9627..cba1e1d3017 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTModuleProviders.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTModuleProviders.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -28,10 +29,10 @@ const MODULE_PROVIDERS_MM_TEMPLATE_PATH = path.join(
 );
 
 function generateRCTModuleProviders(
-  projectRoot,
-  pkgJson,
-  libraries,
-  outputDir,
+  projectRoot /*: string */,
+  pkgJson /*: $FlowFixMe */,
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+  outputDir /*: string */,
 ) {
   fs.mkdirSync(outputDir, {recursive: true});
   // Generate Header File
@@ -42,7 +43,7 @@ function generateRCTModuleProviders(
   codegenLog(`Generated artifact: ${finalPathH}`);
 
   codegenLog('Generating RCTModuleProviders.mm');
-  let modulesInLibraries = {};
+  let modulesInLibraries = {} /*:: as {[string]: Array<$FlowFixMe>}  */;
 
   let app = pkgJson.codegenConfig
     ? {config: pkgJson.codegenConfig, libraryPath: projectRoot}
@@ -64,7 +65,7 @@ function generateRCTModuleProviders(
   // Old API
   moduleLibraries.forEach(({config, libraryPath}) => {
     const libraryName = JSON.parse(
-      fs.readFileSync(path.join(libraryPath, 'package.json')),
+      fs.readFileSync(path.join(libraryPath, 'package.json'), 'utf8'),
     ).name;
 
     if (config.ios?.modulesProvider) {
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTThirdPartyComponents.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTThirdPartyComponents.js
index 53669facbd7..4aea9f734bf 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTThirdPartyComponents.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRCTThirdPartyComponents.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -28,7 +29,10 @@ const THIRD_PARTY_COMPONENTS_MM_TEMPLATE_PATH = path.join(
   'RCTThirdPartyComponentsProviderMM.template',
 );
 
-function generateRCTThirdPartyComponents(libraries, outputDir) {
+function generateRCTThirdPartyComponents(
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+  outputDir /*: string */,
+) {
   fs.mkdirSync(outputDir, {recursive: true});
   // Generate Header File
   codegenLog('Generating RCTThirdPartyComponentsProvider.h');
@@ -41,7 +45,7 @@ function generateRCTThirdPartyComponents(libraries, outputDir) {
   codegenLog(`Generated artifact: ${finalPathH}`);
 
   codegenLog('Generating RCTThirdPartyComponentsProvider.mm');
-  let componentsInLibraries = {};
+  let componentsInLibraries = {} /*:: as {[string]: Array<$FlowFixMe>} */;
 
   const componentLibraries = libraries.filter(({config, libraryPath}) => {
     if (isReactNativeCoreLibrary(config.name) || config.type === 'modules') {
@@ -50,13 +54,13 @@ function generateRCTThirdPartyComponents(libraries, outputDir) {
     return true;
   });
 
-  const librariesToCrawl = {};
+  const librariesToCrawl = {} /*:: as {[string]: $FlowFixMe} */;
 
   // Old API
   componentLibraries.forEach(library => {
     const {config, libraryPath} = library;
     const libraryName = JSON.parse(
-      fs.readFileSync(path.join(libraryPath, 'package.json')),
+      fs.readFileSync(path.join(libraryPath, 'package.json'), 'utf8'),
     ).name;
 
     librariesToCrawl[libraryName] = library;
@@ -140,7 +144,10 @@ function generateRCTThirdPartyComponents(libraries, outputDir) {
 
 // Given a path, return the paths of all the files with extension .mm in
 // the path dir and all its subdirectories.
-function findFilesWithExtension(filePath, extension) {
+function findFilesWithExtension(
+  filePath /*: string */,
+  extension /*: string */,
+) /*: Array<string> */ {
   const files = [];
   const dir = fs.readdirSync(filePath);
   dir.forEach(file => {
@@ -172,7 +179,7 @@ function findFilesWithExtension(filePath, extension) {
 
 // Given a filepath, read the file and look for a string that starts with 'Class<RCTComponentViewProtocol> '
 // and ends with 'Cls(void)'. Return the string between the two.
-function findRCTComponentViewProtocolClass(filepath) {
+function findRCTComponentViewProtocolClass(filepath /*: string */) {
   const fileContent = fs.readFileSync(filepath, 'utf8');
   const regex = /Class<RCTComponentViewProtocol> (.*)Cls\(/;
   const match = fileContent.match(regex);
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRNCoreComponentsIOS.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRNCoreComponentsIOS.js
index ced30a1a3c1..908d4e10ac8 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRNCoreComponentsIOS.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateRNCoreComponentsIOS.js
@@ -4,6 +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 strict-local
  * @format
  */
 
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateReactCodegenPodspec.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateReactCodegenPodspec.js
index 8ec3091e732..d5d932229dc 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateReactCodegenPodspec.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateReactCodegenPodspec.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -25,10 +26,10 @@ const REACT_CODEGEN_PODSPEC_TEMPLATE_PATH = path.join(
 );
 
 function generateReactCodegenPodspec(
-  appPath,
-  appPkgJson,
-  outputPath,
-  baseOutputPath,
+  appPath /*: string */,
+  appPkgJson /*: $FlowFixMe */,
+  outputPath /*: string */,
+  baseOutputPath /*: string */,
 ) {
   const inputFiles = getInputFiles(appPath, appPkgJson);
   const codegenScript = codegenScripts(appPath, baseOutputPath);
@@ -42,8 +43,8 @@ function generateReactCodegenPodspec(
   codegenLog(`Generated podspec: ${finalPathPodspec}`);
 }
 
-function getInputFiles(appPath, appPkgJSon) {
-  const jsSrcsDir = appPkgJSon.codegenConfig?.jsSrcsDir;
+function getInputFiles(appPath /*: string */, appPkgJson /*: $FlowFixMe */) {
+  const jsSrcsDir = appPkgJson.codegenConfig?.jsSrcsDir;
   if (!jsSrcsDir) {
     return '[]';
   }
@@ -70,7 +71,7 @@ function getInputFiles(appPath, appPkgJSon) {
   return `[${list}]`;
 }
 
-function codegenScripts(appPath, outputPath) {
+function codegenScripts(appPath /*: string */, outputPath /*: string */) {
   const relativeAppPath = path.relative(outputPath, appPath);
   return `<<-SCRIPT
 pushd "$PODS_ROOT/../" > /dev/null
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateSchemaInfos.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateSchemaInfos.js
index a222b7f211e..2137c5f9eab 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateSchemaInfos.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateSchemaInfos.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -15,11 +16,17 @@ const fs = require('fs');
 const glob = require('glob');
 const path = require('path');
 
-function generateSchemaInfos(libraries) {
+function generateSchemaInfos(
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+) /*: Array<$FlowFixMe> */ {
+  // $FlowFixMe[incompatible-call]
   return libraries.map(generateSchemaInfo);
 }
 
-function generateSchemaInfo(library, platform) {
+function generateSchemaInfo(
+  library /*: $FlowFixMe */,
+  platform /*: string */,
+) /*: $FlowFixMe */ {
   const pathToJavaScriptSources = path.join(
     library.libraryPath,
     library.config.jsSrcsDir,
@@ -45,7 +52,10 @@ function generateSchemaInfo(library, platform) {
 
 const APPLE_PLATFORMS = ['ios', 'macos', 'tvos', 'visionos'];
 
-function extractSupportedApplePlatforms(dependency, dependencyPath) {
+function extractSupportedApplePlatforms(
+  dependency /*: string */,
+  dependencyPath /*: string */,
+) /*: ?{[string]: boolean} */ {
   codegenLog('Searching for podspec in the project dependencies.', true);
   const podspecs = glob.sync('*.podspec', {cwd: dependencyPath});
 
@@ -80,7 +90,7 @@ function extractSupportedApplePlatforms(dependency, dependencyPath) {
         getCocoaPodsPlatformKey(platform),
       ),
     }),
-    {},
+    {} /*:: as {[string]: boolean} */,
   );
 
   const supportedPlatformsList = Object.keys(supportedPlatformsMap).filter(
@@ -99,7 +109,7 @@ function extractSupportedApplePlatforms(dependency, dependencyPath) {
 }
 
 // Cocoapods specific platform keys
-function getCocoaPodsPlatformKey(platformName) {
+function getCocoaPodsPlatformKey(platformName /*: string */) {
   if (platformName === 'macos') {
     return 'osx';
   }
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateUnstableModulesRequiringMainQueueSetupProvider.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateUnstableModulesRequiringMainQueueSetupProvider.js
index 4187a53bf2d..4d2ea86017e 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/generateUnstableModulesRequiringMainQueueSetupProvider.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/generateUnstableModulesRequiringMainQueueSetupProvider.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -27,12 +28,12 @@ const UNSTABLE_MODULES_REQUIRING_MAIN_QUEUE_SETUP_PROVIDER_MM_TEMPLATE_PATH =
   );
 
 function generateUnstableModulesRequiringMainQueueSetupProvider(
-  libraries,
-  outputDir,
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+  outputDir /*: string */,
 ) {
   const iosAnnotations = parseiOSAnnotations(libraries);
 
-  const modulesRequiringMainQueueSetup = new Set();
+  const modulesRequiringMainQueueSetup = new Set /*::<string>*/();
 
   // Old API
   libraries.forEach(library => {
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/index.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/index.js
index b062ad6d798..002273410bd 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/index.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/index.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -58,11 +59,11 @@ const path = require('path');
  * @throws If it can't find a cli for the CodeGen.
  */
 function execute(
-  projectRoot,
-  targetPlatform,
-  baseOutputPath,
-  source,
-  runReactNativeCodegen = true,
+  projectRoot /*: string */,
+  targetPlatform /*: string */,
+  baseOutputPath /*: string */,
+  source /*: string */,
+  runReactNativeCodegen /*: boolean */ = true,
 ) {
   try {
     codegenLog(`Analyzing ${path.join(projectRoot, 'package.json')}`);
@@ -161,7 +162,10 @@ function execute(
   return;
 }
 
-function readOutputDirFromPkgJson(pkgJson, platform) {
+function readOutputDirFromPkgJson(
+  pkgJson /*: $FlowFixMe */,
+  platform /*: string */,
+) {
   const codegenConfig = pkgJson.codegenConfig;
   if (codegenConfig == null || typeof codegenConfig !== 'object') {
     return null;
@@ -179,12 +183,19 @@ function readOutputDirFromPkgJson(pkgJson, platform) {
   return null;
 }
 
-function computeOutputPath(projectRoot, baseOutputPath, pkgJson, platform) {
+function computeOutputPath(
+  projectRoot /*: string */,
+  baseOutputPath /*: string */,
+  pkgJson /*: $FlowFixMe */,
+  platform /*: string */,
+) {
   if (baseOutputPath == null) {
     const outputDirFromPkgJson = readOutputDirFromPkgJson(pkgJson, platform);
     if (outputDirFromPkgJson != null) {
+      // $FlowFixMe[reassign-const]
       baseOutputPath = path.join(projectRoot, outputDirFromPkgJson);
     } else {
+      // $FlowFixMe[reassign-const]
       baseOutputPath = projectRoot;
     }
   }
@@ -201,7 +212,7 @@ function computeOutputPath(projectRoot, baseOutputPath, pkgJson, platform) {
   return baseOutputPath;
 }
 
-function defaultOutputPathForAndroid(baseOutputPath) {
+function defaultOutputPathForAndroid(baseOutputPath /*: string */) {
   return path.join(
     baseOutputPath,
     'android',
@@ -213,11 +224,14 @@ function defaultOutputPathForAndroid(baseOutputPath) {
   );
 }
 
-function defaultOutputPathForIOS(baseOutputPath) {
+function defaultOutputPathForIOS(baseOutputPath /*: string */) {
   return path.join(baseOutputPath, 'build', 'generated', 'ios');
 }
 
-function mustGenerateNativeCode(includeLibraryPath, schemaInfo) {
+function mustGenerateNativeCode(
+  includeLibraryPath /*: string */,
+  schemaInfo /*: $FlowFixMe */,
+) {
   // If library's 'codegenConfig' sets 'includesGeneratedCode' to 'true',
   // then we assume that native code is shipped with the library,
   // and we don't need to generate it.
diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js b/packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js
index d78cd074878..d5c573d5c5a 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -17,11 +18,13 @@ const {execSync} = require('child_process');
 const fs = require('fs');
 const path = require('path');
 
-function pkgJsonIncludesGeneratedCode(pkgJson) {
+function pkgJsonIncludesGeneratedCode(
+  pkgJson /*: $FlowFixMe */,
+) /*: boolean */ {
   return pkgJson.codegenConfig && pkgJson.codegenConfig.includesGeneratedCode;
 }
 
-const codegenLog = (text, info = false) => {
+const codegenLog = (text /*: string */, info /*: boolean */ = false) => {
   // ANSI escape codes for colors and formatting
   const reset = '\x1b[0m';
   const cyan = '\x1b[36m';
@@ -32,12 +35,12 @@ const codegenLog = (text, info = false) => {
   console.log(`${cyan}${bold}[Codegen]${reset} ${color}${text}${reset}`);
 };
 
-function readPkgJsonInDirectory(dir) {
+function readPkgJsonInDirectory(dir /*: string */) /*: $FlowFixMe */ {
   const pkgJsonPath = path.join(dir, 'package.json');
   if (!fs.existsSync(pkgJsonPath)) {
     throw `[Codegen] Error: ${pkgJsonPath} does not exist.`;
   }
-  return JSON.parse(fs.readFileSync(pkgJsonPath));
+  return JSON.parse(fs.readFileSync(pkgJsonPath, 'utf8'));
 }
 
 function buildCodegenIfNeeded() {
@@ -69,7 +72,7 @@ function buildCodegenIfNeeded() {
 // we don't know whether they will be populated up until the end of the process.
 //
 // @parameter filepath: the root path from which we want to remove the empty files and folders.
-function cleanupEmptyFilesAndFolders(filepath) {
+function cleanupEmptyFilesAndFolders(filepath /*: string */) {
   const stats = fs.statSync(filepath);
 
   if (stats.isFile() && stats.size === 0) {
@@ -94,20 +97,25 @@ function cleanupEmptyFilesAndFolders(filepath) {
   }
 }
 
-function readReactNativeConfig(projectRoot) {
+function readReactNativeConfig(projectRoot /*: string */) /*: $FlowFixMe */ {
   const rnConfigFilePath = path.resolve(projectRoot, 'react-native.config.js');
 
   if (!fs.existsSync(rnConfigFilePath)) {
     return {};
   }
 
+  // $FlowIgnore[unsupported-syntax]
   return require(rnConfigFilePath);
 }
 
 /**
  * Finding libraries!
  */
-function findCodegenEnabledLibraries(pkgJson, projectRoot, reactNativeConfig) {
+function findCodegenEnabledLibraries(
+  pkgJson /*: $FlowFixMe */,
+  projectRoot /*: string */,
+  reactNativeConfig /*: $FlowFixMe */,
+) /*: Array<$FlowFixMe> */ {
   const projectLibraries = findProjectRootLibraries(pkgJson, projectRoot);
   if (pkgJsonIncludesGeneratedCode(pkgJson)) {
     return projectLibraries;
@@ -120,7 +128,10 @@ function findCodegenEnabledLibraries(pkgJson, projectRoot, reactNativeConfig) {
   }
 }
 
-function findProjectRootLibraries(pkgJson, projectRoot) {
+function findProjectRootLibraries(
+  pkgJson /*: $FlowFixMe */,
+  projectRoot /*: string */,
+) /*: Array<$FlowFixMe> */ {
   codegenLog('Searching for codegen-enabled libraries in the app.', true);
 
   if (pkgJson.codegenConfig == null) {
@@ -138,7 +149,10 @@ function findProjectRootLibraries(pkgJson, projectRoot) {
   return extractLibrariesFromJSON(pkgJson, projectRoot);
 }
 
-function findLibrariesFromReactNativeConfig(projectRoot, rnConfig) {
+function findLibrariesFromReactNativeConfig(
+  projectRoot /*: string */,
+  rnConfig /*: $FlowFixMe */,
+) /*: Array<$FlowFixMe> */ {
   codegenLog(
     `Searching for codegen-enabled libraries in react-native.config.js`,
     true,
@@ -168,7 +182,10 @@ function findLibrariesFromReactNativeConfig(projectRoot, rnConfig) {
   });
 }
 
-function findExternalLibraries(pkgJson, projectRoot) {
+function findExternalLibraries(
+  pkgJson /*: $FlowFixMe */,
+  projectRoot /*: string */,
+) /*: Array<$FlowFixMe> */ {
   const dependencies = {
     ...pkgJson.dependencies,
     ...pkgJson.devDependencies,
@@ -201,13 +218,16 @@ function findExternalLibraries(pkgJson, projectRoot) {
         return [];
       }
     }
-    const configFile = JSON.parse(fs.readFileSync(configFilePath));
+    const configFile = JSON.parse(fs.readFileSync(configFilePath, 'utf8'));
     const codegenConfigFileDir = path.dirname(configFilePath);
     return extractLibrariesFromJSON(configFile, codegenConfigFileDir);
   });
 }
 
-function extractLibrariesFromJSON(configFile, dependencyPath) {
+function extractLibrariesFromJSON(
+  configFile /*: $FlowFixMe */,
+  dependencyPath /*: string */,
+) /*: Array<$FlowFixMe> */ {
   if (configFile.codegenConfig == null) {
     return [];
   }
@@ -226,7 +246,7 @@ function extractLibrariesFromJSON(configFile, dependencyPath) {
   }
 }
 
-function printDeprecationWarningIfNeeded(dependency) {
+function printDeprecationWarningIfNeeded(dependency /*: string */) {
   if (dependency === REACT_NATIVE) {
     return;
   }
@@ -264,7 +284,10 @@ function printDeprecationWarningIfNeeded(dependency) {
   `);
 }
 
-function extractLibrariesFromConfigurationArray(configFile, dependencyPath) {
+function extractLibrariesFromConfigurationArray(
+  configFile /*: $FlowFixMe */,
+  dependencyPath /*: string */,
+) {
   return configFile.codegenConfig.libraries.map(config => {
     return {
       config,
@@ -273,7 +296,7 @@ function extractLibrariesFromConfigurationArray(configFile, dependencyPath) {
   });
 }
 
-function isReactNativeCoreLibrary(libraryName) {
+function isReactNativeCoreLibrary(libraryName /*: string */) /*: boolean */ {
   return libraryName in CORE_LIBRARIES_WITH_OUTPUT_FOLDER;
 }
 
@@ -299,9 +322,11 @@ function isReactNativeCoreLibrary(libraryName) {
  * Validates that modules are defined in at most one library.
  * Validates that components are defined in at most one library.
  */
-function parseiOSAnnotations(libraries) {
-  const mLibraryMap = {};
-  const cLibraryMap = {};
+function parseiOSAnnotations(
+  libraries /*: $ReadOnlyArray<$FlowFixMe> */,
+) /*: {[string]: $FlowFixMe} */ {
+  const mLibraryMap = {} /*:: as {[string]: $FlowFixMe} */;
+  const cLibraryMap = {} /*:: as {[string]: $FlowFixMe} */;
   const map = {};
 
   for (const library of libraries) {
@@ -351,7 +376,7 @@ function parseiOSAnnotations(libraries) {
       return `  Component { "${moduleName}" } => Libraries{ ${libraryNamesString} }\n`;
     });
 
-  if (moduleConflicts.length > 0 || componentConflicts.legnth > 0) {
+  if (moduleConflicts.length > 0 || componentConflicts.length > 0) {
     throw new Error(
       'Some components or modules are declared in more than one libraries: \n' +
         [...moduleConflicts, ...componentConflicts].join('\n'),
@@ -361,9 +386,9 @@ function parseiOSAnnotations(libraries) {
   return map;
 }
 
-function getLibraryName(library) {
+function getLibraryName(library /*: $FlowFixMe */) {
   return JSON.parse(
-    fs.readFileSync(path.join(library.libraryPath, 'package.json')),
+    fs.readFileSync(path.join(library.libraryPath, 'package.json'), 'utf8'),
   ).name;
 }
 
@@ -372,7 +397,10 @@ function getLibraryName(library) {
  *
  * This is needed when selectively disabling libraries in react-native.config.js since codegen should exclude those libraries as well.
  */
-function findDisabledLibrariesByPlatform(reactNativeConfig, platform) {
+function findDisabledLibrariesByPlatform(
+  reactNativeConfig /*: $FlowFixMe */,
+  platform /*: string */,
+) /*: Array<$FlowFixMe> */ {
   const dependencies = reactNativeConfig.dependencies ?? {};
 
   return Object.keys(dependencies).filter(
diff --git a/packages/react-native/scripts/codegen/generate-specs-cli-executor.js b/packages/react-native/scripts/codegen/generate-specs-cli-executor.js
index ece43d63b21..a50afb5e673 100644
--- a/packages/react-native/scripts/codegen/generate-specs-cli-executor.js
+++ b/packages/react-native/scripts/codegen/generate-specs-cli-executor.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -14,22 +15,26 @@ const fs = require('fs');
 const path = require('path');
 
 const GENERATORS = {
-  all: {
-    android: ['componentsAndroid', 'modulesAndroid', 'modulesCxx'],
-    ios: ['componentsIOS', 'modulesIOS', 'modulesCxx'],
-  },
-  components: {
-    android: ['componentsAndroid'],
-    ios: ['componentsIOS'],
-  },
-  modules: {
-    android: ['modulesAndroid', 'modulesCxx'],
-    ios: ['modulesIOS', 'modulesCxx'],
-  },
-};
+    all: {
+      android: ['componentsAndroid', 'modulesAndroid', 'modulesCxx'],
+      ios: ['componentsIOS', 'modulesIOS', 'modulesCxx'],
+    },
+    components: {
+      android: ['componentsAndroid'],
+      ios: ['componentsIOS'],
+    },
+    modules: {
+      android: ['modulesAndroid', 'modulesCxx'],
+      ios: ['modulesIOS', 'modulesCxx'],
+    },
+  } /*:: as {[string]: {[string]: $ReadOnlyArray<string>}} */;
 
-function createOutputDirectoryIfNeeded(outputDirectory, libraryName) {
+function createOutputDirectoryIfNeeded(
+  outputDirectory /*: string */,
+  libraryName /*: string */,
+) {
   if (!outputDirectory) {
+    // $FlowFixMe[reassign-const]
     outputDirectory = path.resolve(__dirname, '..', 'Libraries', libraryName);
   }
   fs.mkdirSync(outputDirectory, {recursive: true});
@@ -43,7 +48,7 @@ function createOutputDirectoryIfNeeded(outputDirectory, libraryName) {
  * @return a valid schema
  * @throw an Error if the schema doesn't exists in a given path or if it can't be parsed.
  */
-function readAndParseSchema(schemaPath) {
+function readAndParseSchema(schemaPath /*: string */) {
   const schemaText = fs.readFileSync(schemaPath, 'utf-8');
 
   if (schemaText == null) {
@@ -57,20 +62,20 @@ function readAndParseSchema(schemaPath) {
   }
 }
 
-function validateLibraryType(libraryType) {
+function validateLibraryType(libraryType /*: string */) {
   if (GENERATORS[libraryType] == null) {
     throw new Error(`Invalid library type. ${libraryType}`);
   }
 }
 
 function generateSpecFromInMemorySchema(
-  platform,
-  schema,
-  outputDirectory,
-  libraryName,
-  packageName,
-  libraryType,
-  useLocalIncludePaths,
+  platform /*: string */,
+  schema /*: string */,
+  outputDirectory /*: string */,
+  libraryName /*: string */,
+  packageName /*: string */,
+  libraryType /*: string */,
+  useLocalIncludePaths /*: boolean */,
 ) {
   validateLibraryType(libraryType);
   createOutputDirectoryIfNeeded(outputDirectory, libraryName);
@@ -105,13 +110,14 @@ function generateSpecFromInMemorySchema(
 }
 
 function generateSpec(
-  platform,
-  schemaPath,
-  outputDirectory,
-  libraryName,
-  packageName,
-  libraryType,
+  platform /*: string */,
+  schemaPath /*: string */,
+  outputDirectory /*: string */,
+  libraryName /*: string */,
+  packageName /*: string */,
+  libraryType /*: string */,
 ) {
+  // $FlowFixMe[incompatible-call]
   generateSpecFromInMemorySchema(
     platform,
     readAndParseSchema(schemaPath),
@@ -124,5 +130,5 @@ function generateSpec(
 
 module.exports = {
   execute: generateSpec,
-  generateSpecFromInMemorySchema: generateSpecFromInMemorySchema,
+  generateSpecFromInMemorySchema,
 };
diff --git a/packages/react-native/scripts/compose-source-maps.js b/packages/react-native/scripts/compose-source-maps.js
index db9ae1aa5ed..034b7165af1 100755
--- a/packages/react-native/scripts/compose-source-maps.js
+++ b/packages/react-native/scripts/compose-source-maps.js
@@ -5,6 +5,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -14,7 +15,7 @@ const fs = require('fs');
 const {composeSourceMaps} = require('metro-source-map');
 
 const argv = process.argv.slice(2);
-let outputPath;
+let outputPath /*: ?string */;
 for (let i = 0; i < argv.length; ) {
   if (argv[i] === '-o') {
     outputPath = argv[i + 1];
@@ -58,7 +59,7 @@ if (!argv.length) {
   const composedMapJSON = JSON.stringify(
     composeSourceMaps([packagerSourcemap, compilerSourcemap]),
   );
-  if (outputPath) {
+  if (outputPath != null) {
     fs.writeFileSync(outputPath, composedMapJSON, 'utf8');
   } else {
     process.stdout.write(composedMapJSON);
diff --git a/packages/react-native/scripts/featureflags/index.js b/packages/react-native/scripts/featureflags/index.js
index 413707af059..14b12078685 100644
--- a/packages/react-native/scripts/featureflags/index.js
+++ b/packages/react-native/scripts/featureflags/index.js
@@ -4,6 +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 strict-local
  * @format
  */
 
diff --git a/packages/react-native/scripts/featureflags/templates/android/ReactNativeFeatureFlags.kt-template.js b/packages/react-native/scripts/featureflags/templates/android/ReactNativeFeatureFlags.kt-template.js
index 15c8ef7721b..878fddd757f 100644
--- a/packages/react-native/scripts/featureflags/templates/android/ReactNativeFeatureFlags.kt-template.js
+++ b/packages/react-native/scripts/featureflags/templates/android/ReactNativeFeatureFlags.kt-template.js
@@ -1,10 +1,3 @@
-/**
- * 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.
- */
-
 /**
  * Copyright (c) Meta Platforms, Inc. and affiliates.
  *
diff --git a/packages/react-native/scripts/generate-codegen-artifacts.js b/packages/react-native/scripts/generate-codegen-artifacts.js
index b77bbad9e3d..30ef4de6538 100644
--- a/packages/react-native/scripts/generate-codegen-artifacts.js
+++ b/packages/react-native/scripts/generate-codegen-artifacts.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -33,4 +34,5 @@ const argv = yargs
   .usage('Usage: $0 -p [path to app] -t [target platform] -o [output path]')
   .demandOption(['p', 't']).argv;
 
+// $FlowFixMe[prop-missing]
 executor.execute(argv.path, argv.targetPlatform, argv.outputPath, argv.source);
diff --git a/packages/react-native/scripts/generate-provider-cli.js b/packages/react-native/scripts/generate-provider-cli.js
index 22141ce8b7e..aa9d4acd293 100644
--- a/packages/react-native/scripts/generate-provider-cli.js
+++ b/packages/react-native/scripts/generate-provider-cli.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -34,11 +35,15 @@ const argv = yargs
   ).argv;
 
 const GENERATORS = {
-  android: [],
-  ios: ['providerIOS'],
-};
+    android: [],
+    ios: ['providerIOS'],
+  } /*:: as {[string]: $ReadOnlyArray<string>} */;
 
-function generateProvider(platform, schemaListPath, outputDirectory) {
+function generateProvider(
+  platform /*: string */,
+  schemaListPath /*: string */,
+  outputDirectory /*: string */,
+) {
   const schemaListText = fs.readFileSync(schemaListPath, 'utf-8');
 
   if (schemaListText == null) {
@@ -57,7 +62,7 @@ function generateProvider(platform, schemaListPath, outputDirectory) {
     throw new Error(`Can't parse schema to JSON. ${schemaListPath}`);
   }
 
-  const schemas = {};
+  const schemas = {} /*:: as {[string]: $FlowFixMe} */;
   try {
     for (const libraryName of Object.keys(schemaPaths)) {
       const tmpSchemaText = fs.readFileSync(schemaPaths[libraryName], 'utf-8');
@@ -83,6 +88,7 @@ function generateProvider(platform, schemaListPath, outputDirectory) {
 }
 
 function main() {
+  // $FlowFixMe[prop-missing]
   generateProvider(argv.platform, argv.schemaListPath, argv.outputDir);
 }
 
diff --git a/packages/react-native/scripts/generate-specs-cli.js b/packages/react-native/scripts/generate-specs-cli.js
index 2c3a0eb78b1..f8cd1fa3de7 100644
--- a/packages/react-native/scripts/generate-specs-cli.js
+++ b/packages/react-native/scripts/generate-specs-cli.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -49,11 +50,17 @@ const argv = yargs
 
 function main() {
   executor.execute(
+    // $FlowFixMe[prop-missing]
     argv.platform,
+    // $FlowFixMe[prop-missing]
     argv.schemaPath,
+    // $FlowFixMe[prop-missing]
     argv.outputDir,
+    // $FlowFixMe[prop-missing]
     argv.libraryName,
+    // $FlowFixMe[prop-missing]
     argv.javaPackageName,
+    // $FlowFixMe[prop-missing]
     argv.libraryType,
   );
 }
diff --git a/packages/react-native/scripts/hermes/__tests__/hermes-utils-test.js b/packages/react-native/scripts/hermes/__tests__/hermes-utils-test.js
index 300d4e3b08f..d735445b071 100644
--- a/packages/react-native/scripts/hermes/__tests__/hermes-utils-test.js
+++ b/packages/react-native/scripts/hermes/__tests__/hermes-utils-test.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -35,8 +36,9 @@ const hermesTagSha = '5244f819b2f3949ca94a3a1bf75d54a8ed59d94a';
 const ROOT_DIR = path.normalize(path.join(__dirname, '../../..'));
 const SDKS_DIR = path.join(ROOT_DIR, 'sdks');
 
-let execCalls, spawnCalls;
-let fs;
+let execCalls: $FlowFixMe;
+let spawnCalls: $FlowFixMe;
+let fs: $FlowFixMe;
 
 jest.mock('child_process', () => ({
   execSync: jest.fn((command, options) => {
@@ -153,6 +155,7 @@ describe('hermes-utils', () => {
         }),
     );
     fs = require('fs');
+    // $FlowFixMe[prop-missing]
     fs.reset();
 
     populateMockFilesystemWithHermesBuildScripts();
diff --git a/packages/react-native/scripts/hermes/bump-hermes-version.js b/packages/react-native/scripts/hermes/bump-hermes-version.js
index 09f2c135f36..3ac8c9711b6 100755
--- a/packages/react-native/scripts/hermes/bump-hermes-version.js
+++ b/packages/react-native/scripts/hermes/bump-hermes-version.js
@@ -5,12 +5,14 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
 'use strict';
 
 const {setHermesTag} = require('./hermes-utils');
+// $FlowFixMe[untyped-import]
 const inquirer = require('inquirer');
 /**
  * This script walks a releaser through bumping the Hermes version for a release.
@@ -27,6 +29,7 @@ let argv = yargs.option('t', {
 }).argv;
 
 async function main() {
+  // $FlowFixMe[prop-missing]
   const hermesTag = argv.tag;
   const {confirmHermesTag} = await inquirer.prompt({
     type: 'confirm',
@@ -42,6 +45,6 @@ async function main() {
   setHermesTag(hermesTag);
 }
 
-main().then(() => {
+void main().then(() => {
   exit(0);
 });
diff --git a/packages/react-native/scripts/hermes/create-tarball.js b/packages/react-native/scripts/hermes/create-tarball.js
index 121d0a81397..7214d5639c4 100644
--- a/packages/react-native/scripts/hermes/create-tarball.js
+++ b/packages/react-native/scripts/hermes/create-tarball.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -41,9 +42,13 @@ let argv = yargs
   }).argv;
 
 async function main() {
+  // $FlowFixMe[prop-missing]
   const hermesDir = argv.inputDir;
+  // $FlowFixMe[prop-missing]
   const buildType = argv.buildType;
+  // $FlowFixMe[prop-missing]
   const excludeDebugSymbols = argv.excludeDebugSymbols;
+  // $FlowFixMe[prop-missing]
   let tarballOutputDir = argv.outputDir;
 
   if (!tarballOutputDir) {
@@ -68,6 +73,6 @@ async function main() {
   return tarballOutputPath;
 }
 
-main().then(() => {
+void main().then(() => {
   process.exit(0);
 });
diff --git a/packages/react-native/scripts/hermes/get-tarball-name.js b/packages/react-native/scripts/hermes/get-tarball-name.js
index 6b9cafa789f..ace7543b5dd 100644
--- a/packages/react-native/scripts/hermes/get-tarball-name.js
+++ b/packages/react-native/scripts/hermes/get-tarball-name.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -24,11 +25,12 @@ let argv = yargs.option('b', {
 }).argv;
 
 async function main() {
+  // $FlowFixMe[prop-missing]
   const tarballName = getHermesPrebuiltArtifactsTarballName(argv.buildType);
   console.log(tarballName);
   return tarballName;
 }
 
-main().then(() => {
+void main().then(() => {
   process.exit(0);
 });
diff --git a/packages/react-native/scripts/hermes/hermes-utils.js b/packages/react-native/scripts/hermes/hermes-utils.js
index eb831e74044..d8e4d45e2f6 100644
--- a/packages/react-native/scripts/hermes/hermes-utils.js
+++ b/packages/react-native/scripts/hermes/hermes-utils.js
@@ -224,9 +224,9 @@ set_target_properties(native-hermesc PROPERTIES
 }
 
 function getHermesPrebuiltArtifactsTarballName(
-  buildType /*: string */,
+  buildType /*:: ?: string */,
 ) /*: string */ {
-  if (!buildType) {
+  if (buildType == null) {
     throw Error('Did not specify build type.');
   }
   return `hermes-ios-${buildType.toLowerCase()}.tar.gz`;
diff --git a/packages/react-native/scripts/hermes/prepare-hermes-for-build.js b/packages/react-native/scripts/hermes/prepare-hermes-for-build.js
index acb35fe0ec7..fb9c95361f4 100644
--- a/packages/react-native/scripts/hermes/prepare-hermes-for-build.js
+++ b/packages/react-native/scripts/hermes/prepare-hermes-for-build.js
@@ -4,6 +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 strict-local
  * @format
  */
 
@@ -23,7 +24,7 @@ const {
   shouldUsePrebuiltHermesC,
 } = require('./hermes-utils');
 
-async function main(isInCI) {
+async function main(isInCI /*: boolean */) {
   if (!shouldBuildHermesFromSource(isInCI)) {
     copyPodSpec();
     return;
@@ -41,6 +42,6 @@ async function main(isInCI) {
 
 const isInCI = process.env.CI === 'true';
 
-main(isInCI).then(() => {
+void main(isInCI).then(() => {
   process.exit(0);
 });
diff --git a/packages/react-native/scripts/packager-reporter.js b/packages/react-native/scripts/packager-reporter.js
index a3f5bd54619..f6ab6a9194f 100644
--- a/packages/react-native/scripts/packager-reporter.js
+++ b/packages/react-native/scripts/packager-reporter.js
@@ -4,17 +4,21 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
 'use strict';
 
+let reporter /*: $FlowFixMe */;
+
 const logPath = process.env.RCT_PACKAGER_LOG_PATH;
 if (logPath != null && logPath !== '') {
   const JsonReporter = require('metro/src/lib/JsonReporter');
   const fs = require('fs');
   const path = require('path');
-  module.exports = class extends JsonReporter {
+  // $FlowFixMe[missing-type-arg]
+  reporter = class extends JsonReporter {
     constructor() {
       fs.mkdirSync(path.dirname(logPath), {
         recursive: true,
@@ -23,5 +27,7 @@ if (logPath != null && logPath !== '') {
     }
   };
 } else {
-  module.exports = require('metro/src/lib/TerminalReporter');
+  reporter = require('metro/src/lib/TerminalReporter');
 }
+
+module.exports = reporter;