use existent file check

Author: SimenB

packages/jest-resolve/src/fileWalkers.ts

@@ -14,7 +14,6 @@ export function clearFsCache(): void {
   checkedPaths.clear();
   checkedRealpathPaths.clear();
   packageContents.clear();
-  packageJsonInDir.clear();
 }
 
 enum IPathType {
@@ -89,22 +88,9 @@ export function readPackageCached(path: Config.Path): PkgJson {
   return result;
 }
 
-const packageJsonInDir = new Map<string, boolean>();
-function directoryHasPackageJson(file: Config.Path): boolean {
-  let cachedValue = packageJsonInDir.get(file);
-
-  if (cachedValue != null) {
-    return cachedValue;
-  }
-
-  cachedValue = fs.existsSync(file);
-
-  packageJsonInDir.set(file, cachedValue);
-
-  return cachedValue;
-}
-
-// adapted from https://github.com/lukeed/escalade/blob/2477005062cdbd8407afc90d3f48f4930354252b/src/sync.js to use cached `fs.stat` calls
+// adapted from
+// https://github.com/lukeed/escalade/blob/2477005062cdbd8407afc90d3f48f4930354252b/src/sync.js
+// to use cached `fs` calls
 export function findClosestPackageJson(
   start: Config.Path,
 ): Config.Path | undefined {
@@ -115,7 +101,7 @@ export function findClosestPackageJson(
 
   while (true) {
     const pkgJsonFile = resolve(dir, './package.json');
-    const hasPackageJson = directoryHasPackageJson(pkgJsonFile);
+    const hasPackageJson = isFile(pkgJsonFile);
 
     if (hasPackageJson) {
       return pkgJsonFile;