From 3f4fbca7213fbfad92758bdf7a135344f9c51452 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 15 Apr 2026 08:14:06 +0000
Subject: [PATCH] perf: optimize `fs.readFileSync` calls by passing encoding
 directly

Replaced `fs.readFileSync(path).toString()` with `fs.readFileSync(path, 'utf8')`
in `@expo/cli` and `@expo/config-plugins`. This micro-optimization directly passes
the encoding to the filesystem API, which avoids an intermediate `Buffer` allocation
and subsequent garbage collection overhead. Added inline comments to document the
performance benefit.

Co-authored-by: vishnu-madhavan-git <237662584+vishnu-madhavan-git@users.noreply.github.com>
---
 .jules/bolt.md                                       | 0
 packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts  | 5 +++--
 packages/@expo/config-plugins/src/android/Package.ts | 6 ++++--
 3 files changed, 7 insertions(+), 4 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 00000000000000..e69de29bb2d1d6
diff --git a/packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts b/packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts
index dab487df678413..63522ff8aaeb0f 100644
--- a/packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts
+++ b/packages/@expo/cli/src/utils/mergeGitIgnorePaths.ts
@@ -35,8 +35,9 @@ export function mergeGitIgnorePaths(
     return null;
   }
 
-  const targetGitIgnore = fs.readFileSync(targetGitIgnorePath).toString();
-  const sourceGitIgnore = fs.readFileSync(sourceGitIgnorePath).toString();
+  // Performance: Pass 'utf8' encoding directly to avoid intermediate Buffer allocation
+  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) {
diff --git a/packages/@expo/config-plugins/src/android/Package.ts b/packages/@expo/config-plugins/src/android/Package.ts
index 96222ebf4ba553..8f360326f69252 100644
--- a/packages/@expo/config-plugins/src/android/Package.ts
+++ b/packages/@expo/config-plugins/src/android/Package.ts
@@ -125,7 +125,8 @@ 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();
+        // Performance: Pass 'utf8' encoding directly to avoid intermediate Buffer allocation
+        let contents = fs.readFileSync(filepath, 'utf8');
         contents = contents.replace(
           new RegExp(transformJavaClassDescriptor(currentPackageName).replace(/\//g, '\\/'), 'g'),
           transformJavaClassDescriptor(packageName)
@@ -207,7 +208,8 @@ export async function renamePackageOnDiskForType({
   filesToUpdate.forEach((filepath: string) => {
     try {
       if (fs.lstatSync(filepath).isFile()) {
-        let contents = fs.readFileSync(filepath).toString();
+        // Performance: Pass 'utf8' encoding directly to avoid intermediate Buffer allocation
+        let contents = fs.readFileSync(filepath, 'utf8');
         if (path.extname(filepath) === '.kt') {
           contents = replacePackageName(contents, currentPackageName, kotlinSanitizedPackageName);
         } else {