⚡ Bolt: [performance improvement] Avoid intermediate buffer allocations in fs reads

packages/@expo/cli/src/events/stream.ts

@@ -61,7 +61,7 @@ export class LogStream extends EventEmitter implements NodeJS.WritableStream {
 
       const outputLength = Buffer.byteLength(this.#output);
       if (outputLength > written) {
-        const output = Buffer.from(this.#output).subarray(written).toString();
+        const output = Buffer.from(this.#output).subarray(written).toString('utf8');
         this.#len -= this.#output.length - output.length;
         this.#output = output;
       } else {

packages/@expo/cli/src/export/exportDomComponents.ts

@@ -139,7 +139,10 @@ export function transformDomEntryForMd5Filename({
 }): PlatformMetadata['assets'] {
   const htmlContent = files.get(htmlOutputName);
   assert(htmlContent);
-  const htmlMd5 = crypto.createHash('md5').update(htmlContent.contents.toString()).digest('hex');
+  const htmlMd5 = crypto
+    .createHash('md5')
+    .update(htmlContent.contents.toString('utf8'))
+    .digest('hex');
   const htmlMd5Filename = `${DOM_COMPONENTS_BUNDLE_DIR}/${htmlMd5}.html`;
   files.set(htmlMd5Filename, htmlContent);
   files.delete(htmlOutputName);
@@ -167,7 +170,10 @@ export function transformNativeBundleForMd5Filename({
 }) {
   const htmlContent = files.get(htmlOutputName);
   assert(htmlContent);
-  const htmlMd5 = crypto.createHash('md5').update(htmlContent.contents.toString()).digest('hex');
+  const htmlMd5 = crypto
+    .createHash('md5')
+    .update(htmlContent.contents.toString('utf8'))
+    .digest('hex');
   const hash = crypto.createHash('md5').update(domComponentReference).digest('hex');
   for (const artifact of nativeBundle.artifacts) {
     if (artifact.type !== 'js') {
@@ -188,7 +194,7 @@ export function transformNativeBundleForMd5Filename({
       const search = `${hash}.html`;
       const replace = `${htmlMd5}.html`;
       assert(search.length === replace.length);
-      assetEntity.contents = assetEntity.contents.toString().replaceAll(search, replace);
+      assetEntity.contents = assetEntity.contents.toString('utf8').replaceAll(search, replace);
     }
   }
 }

packages/@expo/cli/src/start/project/__tests__/devices-test.ts

@@ -26,7 +26,7 @@ describe('devices info', () => {
     const file = path.join(projectRoot, '.expo', 'devices.json');
     expect(fs.existsSync(file)).toBe(true);
 
-    const { devices } = JSON.parse(fs.readFileSync(file, 'utf8').toString());
+    const { devices } = JSON.parse(fs.readFileSync(file, 'utf8'));
     expect(devices.length).toBe(1);
     expect(devices[0].installationId).toBe('test-device-id');
   });

packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts

@@ -35,8 +35,8 @@ export function mergeGitIgnorePaths(
     return null;
   }
 
-  const targetGitIgnore = fs.readFileSync(targetGitIgnorePath).toString();
-  const sourceGitIgnore = fs.readFileSync(sourceGitIgnorePath).toString();
+  const targetGitIgnore = fs.readFileSync(targetGitIgnorePath, 'utf8');
+  const sourceGitIgnore = fs.readFileSync(sourceGitIgnorePath, 'utf8');
   const merged = mergeGitIgnoreContents(targetGitIgnore, sourceGitIgnore);
   // Only rewrite the file if it was modified.
   if (merged.contents) {

packages/@expo/cli/src/utils/plist.ts

@@ -22,7 +22,7 @@ export async function parsePlistAsync(plistPath: string) {
 
 export function parsePlistBuffer(contents: Buffer) {
   if (contents[0] === CHAR_CHEVRON_OPEN) {
-    const info = plist.parse(contents.toString());
+    const info = plist.parse(contents.toString('utf8'));
     if (Array.isArray(info)) return info[0];
     return info;
   } else if (contents[0] === CHAR_B_LOWER) {

packages/@expo/config-plugins/src/android/Package.ts

@@ -125,7 +125,7 @@ export async function renameJniOnDiskForType({
   filesToUpdate.forEach((filepath: string) => {
     try {
       if (fs.lstatSync(filepath).isFile() && ['.h', '.cpp'].includes(path.extname(filepath))) {
-        let contents = fs.readFileSync(filepath).toString();
+        let contents = fs.readFileSync(filepath, 'utf8');
         contents = contents.replace(
           new RegExp(transformJavaClassDescriptor(currentPackageName).replace(/\//g, '\\/'), 'g'),
           transformJavaClassDescriptor(packageName)
@@ -207,7 +207,7 @@ export async function renamePackageOnDiskForType({
   filesToUpdate.forEach((filepath: string) => {
     try {
       if (fs.lstatSync(filepath).isFile()) {
-        let contents = fs.readFileSync(filepath).toString();
+        let contents = fs.readFileSync(filepath, 'utf8');
         if (path.extname(filepath) === '.kt') {
           contents = replacePackageName(contents, currentPackageName, kotlinSanitizedPackageName);
         } else {

packages/@expo/config-plugins/src/android/__tests__/Locales-test.ts

@@ -58,7 +58,7 @@ describe('e2e: Android locales', () => {
       },
     };
     const mockJSONFile = {
-      readAsync: (path) => JSON.parse(vol.readFileSync(path).toString()),
+      readAsync: (path) => JSON.parse(vol.readFileSync(path, 'utf8') as string),
     };
     jest.mock('../../utils/XML', () => mockXML);
     jest.mock('@expo/json-file', () => mockJSONFile);
@@ -84,22 +84,25 @@ describe('e2e: Android locales', () => {
       { projectRoot }
     );
 
-    expect(vol.readFileSync('/app/android/app/src/main/res/values-b+es/strings.xml').toString())
-      .toMatchInlineSnapshot(`
+    expect(
+      vol.readFileSync('/app/android/app/src/main/res/values-b+es/strings.xml', 'utf8') as string
+    ).toMatchInlineSnapshot(`
       "<resources>
         <string name="CFBundleDisplayName">"spanish-name"</string>
       </resources>"
     `);
     // backwards compatibility
-    expect(vol.readFileSync('/app/android/app/src/main/res/values-b+en/strings.xml').toString())
-      .toMatchInlineSnapshot(`
+    expect(
+      vol.readFileSync('/app/android/app/src/main/res/values-b+en/strings.xml', 'utf8') as string
+    ).toMatchInlineSnapshot(`
       "<resources>
         <string name="CFBundleDisplayName">"us-name"</string>
         <string name="app_name">"us-name"</string>
       </resources>"
     `);
-    expect(vol.readFileSync('/app/android/app/src/main/res/values-b+en+US/strings.xml').toString())
-      .toMatchInlineSnapshot(`
+    expect(
+      vol.readFileSync('/app/android/app/src/main/res/values-b+en+US/strings.xml', 'utf8') as string
+    ).toMatchInlineSnapshot(`
       "<resources>
         <string name="app_name">"us-name"</string>
       </resources>"

packages/@expo/config-plugins/src/android/__tests__/renamePackageOnDisk-test.ts

@@ -44,24 +44,24 @@ public class SomeClass {
       await renamePackageOnDisk({ android: { package: 'xyz.bront.app' } }, '/myapp');
       const mainActivityPath = '/myapp/android/app/src/main/java/xyz/bront/app/MainActivity.java';
       expect(fs.existsSync(mainActivityPath)).toBeTruthy();
-      expect(fs.readFileSync(mainActivityPath).toString()).toMatch('package xyz.bront.app');
+      expect(fs.readFileSync(mainActivityPath, 'utf8')).toMatch('package xyz.bront.app');
 
       const nestedClassPath =
         '/myapp/android/app/src/main/java/xyz/bront/app/example/SomeClass.java';
       expect(fs.existsSync(nestedClassPath)).toBeTruthy();
-      expect(fs.readFileSync(nestedClassPath).toString()).toMatch('package xyz.bront.app');
-      expect(fs.readFileSync(nestedClassPath).toString()).not.toMatch('com.lololol');
+      expect(fs.readFileSync(nestedClassPath, 'utf8')).toMatch('package xyz.bront.app');
+      expect(fs.readFileSync(nestedClassPath, 'utf8')).not.toMatch('com.lololol');
 
       const buckPath = '/myapp/android/app/BUCK';
-      expect(fs.readFileSync(buckPath).toString()).toMatch('package = "xyz.bront.app"');
-      expect(fs.readFileSync(buckPath).toString()).not.toMatch('com.lololol');
+      expect(fs.readFileSync(buckPath, 'utf8')).toMatch('package = "xyz.bront.app"');
+      expect(fs.readFileSync(buckPath, 'utf8')).not.toMatch('com.lololol');
     });
 
     it('does not clobber itself if package has similar parts', async () => {
       await renamePackageOnDisk({ android: { package: 'com.bront' } }, '/myapp');
       const mainActivityPath = '/myapp/android/app/src/main/java/com/bront/MainActivity.java';
       expect(fs.existsSync(mainActivityPath)).toBeTruthy();
-      expect(fs.readFileSync(mainActivityPath).toString()).toMatch('package com.bront');
+      expect(fs.readFileSync(mainActivityPath, 'utf8')).toMatch('package com.bront');
     });
   });
 });

packages/@expo/prebuild-config/src/plugins/unversioned/expo-splash-screen/__tests__/withAndroidSplashLegacyMainActivity-test.ts

@@ -28,7 +28,7 @@ describe(setSplashScreenLegacyMainActivity, () => {
       },
     };
     const mainActivity = await AndroidConfig.Paths.getMainActivityAsync('/app');
-    let contents = fs.readFileSync(mainActivity.path).toString();
+    let contents = fs.readFileSync(mainActivity.path, 'utf8');
     contents = await setSplashScreenLegacyMainActivity(
       exp,
       { backgroundColor: '#000020', resizeMode: 'native' },

packages/expo-brownfield/plugin/src/common/filesystem.ts

@@ -26,7 +26,7 @@ const maybeReadOverwrittenTemplate = (template: string, platform?: PlatformStrin
   try {
     accessSync(path.join(process.cwd(), '.brownfield-templates'));
     if (existsSync(path.join(process.cwd(), '.brownfield-templates', template))) {
-      return readFileSync(path.join(process.cwd(), '.brownfield-templates', template)).toString();
+      return readFileSync(path.join(process.cwd(), '.brownfield-templates', template), 'utf8');
     }
 
     if (existsSync(path.join(process.cwd(), '.brownfield-templates', platform ?? '.', template))) {
@@ -55,7 +55,7 @@ const readTemplate = (template: string, platform?: PlatformString): string => {
     throw new Error(`Template ${template} doesn't exist at ${templatePath}`);
   }
 
-  return readFileSync(templatePath).toString();
+  return readFileSync(templatePath, 'utf8');
 };
 
 const createFileFromTemplateInternal = (

packages/expo-modules-autolinking/src/reactNativeConfig/__tests__/androidResolver-test.ts

@@ -440,7 +440,7 @@ class CustomReactPackage : TurboReactPackage() {
 }`,
       },
     ])('should handle $description', ({ content }) => {
-      expect(matchNativePackageClassName(path, Buffer.from(content))).toBe('CustomReactPackage');
+      expect(matchNativePackageClassName(path, content)).toBe('CustomReactPackage');
     });
 
     // these are not as exhaustive as they could be, but cover main cases
@@ -462,7 +462,7 @@ public class CustomReactPackage extends SomeOtherPackage {
         content: '',
       },
     ])('should return null for $description', ({ content }) => {
-      expect(matchNativePackageClassName(path, Buffer.from(content))).toBeNull();
+      expect(matchNativePackageClassName(path, content)).toBeNull();
     });
   });
 });

packages/expo-modules-autolinking/src/reactNativeConfig/androidResolver.ts

@@ -143,7 +143,7 @@ export async function parseNativePackageClassNameAsync(
   for await (const entry of scanFilesRecursively(androidDir, undefined, true)) {
     if (entry.name.endsWith('Package.java') || entry.name.endsWith('Package.kt')) {
       try {
-        const contents = await fs.readFile(entry.path);
+        const contents = await fs.readFile(entry.path, 'utf8');
         const matched = matchNativePackageClassName(entry.path, contents);
         if (matched) {
           return matched;
@@ -162,7 +162,7 @@ export async function parseNativePackageClassNameAsync(
   // Search all **/*.{java,kt} files
   for await (const entry of scanFilesRecursively(androidDir, undefined, true)) {
     if (entry.name.endsWith('.java') || entry.name.endsWith('.kt')) {
-      const contents = await fs.readFile(entry.path);
+      const contents = await fs.readFile(entry.path, 'utf8');
       const matched = matchNativePackageClassName(entry.path, contents);
       if (matched) {
         return matched;
@@ -174,15 +174,15 @@ export async function parseNativePackageClassNameAsync(
 
 let lazyReactPackageRegex: RegExp | null = null;
 let lazyTurboReactPackageRegex: RegExp | null = null;
-export function matchNativePackageClassName(_filePath: string, contents: Buffer): string | null {
-  const fileContents = contents.toString();
+export function matchNativePackageClassName(_filePath: string, contents: string): string | null {
+
 
   // [0] Match ReactPackage
   if (!lazyReactPackageRegex) {
     lazyReactPackageRegex =
       /class\s+(\w+[^(\s]*)[\s\w():]*(\s+implements\s+|:)[\s\w():,]*[^{]*ReactPackage/;
   }
-  const matchReactPackage = fileContents.match(lazyReactPackageRegex);
+  const matchReactPackage = contents.match(lazyReactPackageRegex);
   if (matchReactPackage) {
     return matchReactPackage[1];
   }
@@ -192,7 +192,7 @@ export function matchNativePackageClassName(_filePath: string, contents: Buffer)
     lazyTurboReactPackageRegex =
       /class\s+(\w+[^(\s]*)[\s\w():]*(\s+extends\s+|:)[\s\w():,]*[^{]*(Base|Turbo)ReactPackage/;
   }
-  const matchTurboReactPackage = fileContents.match(lazyTurboReactPackageRegex);
+  const matchTurboReactPackage = contents.match(lazyTurboReactPackageRegex);
   if (matchTurboReactPackage) {
     return matchTurboReactPackage[1];
   }

packages/pod-install/src/index.ts

@@ -41,7 +41,7 @@ async function runAsync(maybeProjectDirectory?: string): Promise<void> {
       process.exit(1);
     }
 
-    const jsonData = JSON.parse(readFileSync(packageJsonPath).toString());
+    const jsonData = JSON.parse(readFileSync(packageJsonPath, 'utf8'));
     const hasExpoPackage = jsonData.dependencies?.hasOwnProperty('expo');
 
     if (hasExpoPackage) {