From d398d46d808be03c2c5ae98830d583561c145093 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ma=C3=ABl=20Nison?= <mael@fb.com>
Date: Sat, 3 Nov 2018 13:04:34 -0700
Subject: [PATCH] fs: makes existsSync stop using errors

The previous implementation of `existsSync` was a try/catch on top
of `accessSync`. While conceptually sound it was a performance problem
when running it repeatedly on non-existing files, because `accessSync`
had to create an `Error` object that was immediatly discarded (because
`existsSync` never reports anything else than `true` / `false`).

This implementation simply checks whether the context would have caused
an exception to be thrown, but doesn't actually create it.

Fixes: https://github.com/nodejs/node/issues/24008
---
 lib/fs.js | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/fs.js b/lib/fs.js
index 89c005375f450e..cdcca13c0e6938 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -227,12 +227,19 @@ Object.defineProperty(exists, internalUtil.promisify.custom, {
 // validation errors to users properly out of compatibility concerns.
 // TODO(joyeecheung): deprecate the never-throw-on-invalid-arguments behavior
 function existsSync(path) {
+  let ctx;
+
   try {
-    fs.accessSync(path, F_OK);
-    return true;
-  } catch (e) {
+    path = toPathIfFileURL(path);
+    validatePath(path);
+
+    ctx = { path };
+    binding.access(pathModule.toNamespacedPath(path), F_OK, undefined, ctx);
+  } catch {
     return false;
   }
+
+  return ctx.errno === undefined && ctx.error === undefined;
 }
 
 function readFileAfterOpen(err, fd) {