From 22c39b1ddd2f5f2ed13397b351b05836f7abea54 Mon Sep 17 00:00:00 2001
From: theanarkh <theratliter@gmail.com>
Date: Mon, 10 Oct 2022 23:12:08 +0800
Subject: [PATCH] path: the dot will be added(path.format) if it is not
 specified in `ext`

PR-URL: https://github.com/nodejs/node/pull/44349
Fixes: https://github.com/nodejs/node/issues/44343
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
---
 doc/api/path.md                         | 12 ++++++++++++
 lib/path.js                             |  6 +++++-
 test/parallel/test-path-parse-format.js |  4 ++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/doc/api/path.md b/doc/api/path.md
index 5b66e54f9393d2..81d8189b2ee8ff 100644
--- a/doc/api/path.md
+++ b/doc/api/path.md
@@ -206,6 +206,10 @@ A [`TypeError`][] is thrown if `path` is not a string.
 
 <!-- YAML
 added: v0.11.15
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/44349
+    description: The dot will be added if it is not specified in `ext`.
 -->
 
 * `pathObject` {Object} Any JavaScript object having the following properties:
@@ -255,6 +259,14 @@ path.format({
   ext: '.txt'
 });
 // Returns: '/file.txt'
+
+// The dot will be added if it is not specified in `ext`.
+path.format({
+  root: '/',
+  name: 'file',
+  ext: 'txt'
+});
+// Returns: '/file.txt'
 ```
 
 On Windows:
diff --git a/lib/path.js b/lib/path.js
index e662e50d6c6b4b..920bc698601e5f 100644
--- a/lib/path.js
+++ b/lib/path.js
@@ -127,6 +127,10 @@ function normalizeString(path, allowAboveRoot, separator, isPathSeparator) {
   return res;
 }
 
+function formatExt(ext) {
+  return ext ? `${ext[0] === '.' ? '' : '.'}${ext}` : '';
+}
+
 /**
  * @param {string} sep
  * @param {{
@@ -142,7 +146,7 @@ function _format(sep, pathObject) {
   validateObject(pathObject, 'pathObject');
   const dir = pathObject.dir || pathObject.root;
   const base = pathObject.base ||
-    `${pathObject.name || ''}${pathObject.ext || ''}`;
+    `${pathObject.name || ''}${formatExt(pathObject.ext)}`;
   if (!dir) {
     return base;
   }
diff --git a/test/parallel/test-path-parse-format.js b/test/parallel/test-path-parse-format.js
index e60a0cedae4259..52acd836cce87b 100644
--- a/test/parallel/test-path-parse-format.js
+++ b/test/parallel/test-path-parse-format.js
@@ -224,3 +224,7 @@ function checkFormat(path, testCases) {
     });
   });
 }
+
+// See https://github.com/nodejs/node/issues/44343
+assert.strictEqual(path.format({ name: 'x', ext: 'png' }), 'x.png');
+assert.strictEqual(path.format({ name: 'x', ext: '.png' }), 'x.png');