From dfe46d79035dd7302bb55b84cc445db07e8dde7f Mon Sep 17 00:00:00 2001
From: Pooya Parsa <pyapar@gmail.com>
Date: Thu, 30 Jun 2022 00:49:26 +0200
Subject: [PATCH] fix(extname): handle edge cases wirth leading dot

resolves #21
---
 src/path.ts        | 5 +++--
 test/index.spec.ts | 8 ++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/path.ts b/src/path.ts
index f295bd5..0eab07a 100644
--- a/src/path.ts
+++ b/src/path.ts
@@ -182,9 +182,10 @@ export const toNamespacedPath: typeof path.toNamespacedPath = function (p) {
 }
 
 // extname
+const _EXTNAME_RE = /(?<!^)\.[^/.]+$/
 export const extname: typeof path.extname = function (p) {
-  const segments = normalizeWindowsPath(p).split('/').pop().split('.')
-  return segments.length > 1 ? `.${segments.pop()}` : ''
+  const match = _EXTNAME_RE.exec(normalizeWindowsPath(p))
+  return (match && match[0]) || ''
 }
 
 // relative
diff --git a/test/index.spec.ts b/test/index.spec.ts
index e3e43e5..05098e6 100644
--- a/test/index.spec.ts
+++ b/test/index.spec.ts
@@ -61,6 +61,14 @@ runTest('extname', extname, {
   '/temp/myfile.html': '.html',
   './myfile.html': '.html',
 
+  '.foo': '',
+  '..foo': '.foo',
+  'foo.123': '.123',
+  '..': '',
+  '.': '',
+  './': '',
+  // '...': '.', // TODO: Edge case behavior of Node?
+
   // Windows
   'C:\\temp\\myfile.html': '.html',
   '\\temp\\myfile.html': '.html',