Cache package.json FS lookups in isPackageInProjectDeps

Co-authored-by: NullVoxPopuli <[email protected]>

Author: Copilot

lib/rules/template-missing-invokable.js

@@ -35,22 +35,32 @@ function findNearestPackageJson(startDir) {
   return null;
 }
 
+// Cache: `${pkg}\0${fileDir}` -> boolean. Survives the lifetime of the process
+// (one ESLint run), avoiding repeated FS reads for the same file directory.
+const packageInDepsCache = new Map();
+
 function isPackageInProjectDeps(moduleName, fileDir) {
+  const pkg = rootPackageName(moduleName);
+  const cacheKey = `${pkg}::${fileDir}`;
+  if (packageInDepsCache.has(cacheKey)) {
+    return packageInDepsCache.get(cacheKey);
+  }
+  let result = false;
   try {
     const pkgPath = findNearestPackageJson(fileDir);
-    if (!pkgPath) {
-      return false;
+    if (pkgPath) {
+      const packageJson = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
+      result = Boolean(
+        (packageJson.dependencies && pkg in packageJson.dependencies) ||
+          (packageJson.devDependencies && pkg in packageJson.devDependencies) ||
+          (packageJson.peerDependencies && pkg in packageJson.peerDependencies)
+      );
     }
-    const packageJson = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
-    const pkg = rootPackageName(moduleName);
-    return Boolean(
-      (packageJson.dependencies && pkg in packageJson.dependencies) ||
-        (packageJson.devDependencies && pkg in packageJson.devDependencies) ||
-        (packageJson.peerDependencies && pkg in packageJson.peerDependencies)
-    );
   } catch {
-    return false;
+    result = false;
   }
+  packageInDepsCache.set(cacheKey, result);
+  return result;
 }
 
 /** @type {import('eslint').Rule.RuleModule} */
@@ -89,6 +99,9 @@ module.exports = {
 
   create: (context) => {
     const sourceCode = context.sourceCode;
+    const fileDir = path.dirname(
+      path.resolve(context.getPhysicalFilename?.() ?? context.getFilename())
+    );
 
     // takes a node with a `.path` property
     function checkInvokable(node) {
@@ -97,9 +110,6 @@ module.exports = {
           const matched = context.options[0]?.invokables?.[node.path.head.name];
           if (matched) {
             const [name, moduleName] = matched;
-            const fileDir = path.dirname(
-              path.resolve(context.getPhysicalFilename?.() ?? context.getFilename())
-            );
             const canAutoFix =
               isBuiltinPackage(moduleName) ||
               isPackageInProjectDeps(moduleName, fileDir);