From 4353c6aa69db3ec90adc4a30fd54bbe1f5f0b675 Mon Sep 17 00:00:00 2001
From: James Garbutt <43081j@users.noreply.github.com>
Date: Thu, 9 Jan 2025 15:43:41 +0000
Subject: [PATCH] fix(format): allow calls with partial arguments (#198)

---
 src/_path.ts       | 5 ++++-
 test/index.spec.ts | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/_path.ts b/src/_path.ts
index 84eb4c9..f4be9b2 100644
--- a/src/_path.ts
+++ b/src/_path.ts
@@ -250,7 +250,10 @@ export const dirname: typeof path.dirname = function (p) {
 };
 
 export const format: typeof path.format = function (p) {
-  const segments = [p.root, p.dir, p.base ?? p.name + p.ext].filter(Boolean);
+  const ext = p.ext ? (p.ext.startsWith(".") ? p.ext : `.${p.ext}`) : "";
+  const segments = [p.root, p.dir, p.base ?? (p.name ?? "") + ext].filter(
+    Boolean,
+  ) as string[];
   return normalizeWindowsPath(
     p.root ? resolve(...segments) : segments.join("/"),
   );
diff --git a/test/index.spec.ts b/test/index.spec.ts
index 4dca383..9c1f798 100644
--- a/test/index.spec.ts
+++ b/test/index.spec.ts
@@ -153,6 +153,10 @@ runTest("format", format, [
   [{ root: "/", base: "file.txt", ext: "ignored" }, "/file.txt"],
   [{ root: "/", name: "file", ext: ".txt" }, "/file.txt"],
   [{ name: "file", ext: ".txt" }, "file.txt"],
+  [{ name: "file" }, "file"],
+  [{ ext: "ext" }, ".ext"],
+  [{ ext: ".ext" }, ".ext"],
+  [{ dir: "/foo", name: "file" }, "/foo/file"],
 
   // Windows
   [{ name: "file", base: "file.txt" }, "file.txt"],