From 758c76af58f9e9d41ab41f37d89f196b1140a4bc Mon Sep 17 00:00:00 2001
From: Victor Lin <victor.lin@airbnb.com>
Date: Tue, 4 Feb 2020 12:44:26 -0800
Subject: [PATCH] skip checks in lstat callback

---
 packages/jest-haste-map/src/crawlers/node.ts | 21 ++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/packages/jest-haste-map/src/crawlers/node.ts b/packages/jest-haste-map/src/crawlers/node.ts
index 833f51f80f14..0bcb0fcd82db 100644
--- a/packages/jest-haste-map/src/crawlers/node.ts
+++ b/packages/jest-haste-map/src/crawlers/node.ts
@@ -61,17 +61,26 @@ function find(
           }
         }
 
+        // If we made it here and had dirent support, we know that
+        // this is a normal file and can skip some checks in the lstat callback below
+        let passedFiletypeChecks = typeof entry !== 'string';
+
         activeCalls++;
 
         fs.lstat(file, (err, stat) => {
           activeCalls--;
 
-          // This logic is unnecessary for node > v10.10, but leaving it in
-          // since we need it for backwards-compatibility still.
-          if (!err && stat && !stat.isSymbolicLink()) {
-            if (stat.isDirectory()) {
-              search(file);
-            } else {
+          if (!err && stat) {
+            if (!passedFiletypeChecks) {
+              if (stat.isSymbolicLink()) {
+                // do nothing
+              } else if (stat.isDirectory()) {
+                search(file);
+              } else {
+                passedFiletypeChecks = true;
+              }
+            }
+            if (passedFiletypeChecks) {
               const ext = path.extname(file).substr(1);
               if (extensions.indexOf(ext) !== -1) {
                 result.push([file, stat.mtime.getTime(), stat.size]);