feat(path/unstable): support URL in extname()

path/extname.ts

@@ -22,6 +22,29 @@ import { extname as windowsExtname } from "./windows/extname.ts";
  * @param path Path with extension.
  * @returns The file extension. E.g. returns `.ts` for `file.ts`.
  */
-export function extname(path: string): string {
-  return isWindows ? windowsExtname(path) : posixExtname(path);
+export function extname(path: string): string;
+/**
+ * Return the extension of the path with leading period (".").
+ *
+ * @experimental **UNSTABLE**: New API, yet to be vetted.
+ *
+ * @example Usage
+ * ```ts
+ * import { extname } from "@std/path/extname";
+ * import { assertEquals } from "@std/assert";
+ *
+ * if (Deno.build.os === "windows") {
+ *   assertEquals(extname(new URL("file:///C:/home/user/Documents/image.png")), ".png");
+ * } else {
+ *   assertEquals(extname(new URL("file:///home/user/Documents/image.png")), ".png");
+ * }
+ * ```
+ *
+ * @param path Path with extension.
+ * @returns The file extension. E.g. returns `.ts` for `file.ts`.
+ */
+export function extname(path: URL): string;
+export function extname(path: string | URL): string {
+  // deno-lint-ignore no-explicit-any
+  return isWindows ? windowsExtname(path as any) : posixExtname(path as any);
 }

path/extname_test.ts

@@ -68,6 +68,15 @@ Deno.test("posix.extname()", function () {
   assertEquals(posix.extname("file\\\\"), "");
   assertEquals(posix.extname("file.\\"), ".\\");
   assertEquals(posix.extname("file.\\\\"), ".\\\\");
+
+  assertEquals(
+    posix.extname(new URL("file:///home/user/Documents/image.png")),
+    ".png",
+  );
+  assertEquals(
+    posix.extname(new URL("file:///home/user/Documents")),
+    "",
+  );
 });
 
 Deno.test("windows.extname()", function () {
@@ -87,4 +96,13 @@ Deno.test("windows.extname()", function () {
   assertEquals(windows.extname("file\\\\"), "");
   assertEquals(windows.extname("file.\\"), ".");
   assertEquals(windows.extname("file.\\\\"), ".");
+
+  assertEquals(
+    windows.extname(new URL("file:///C:/home/user/Documents/image.png")),
+    ".png",
+  );
+  assertEquals(
+    windows.extname(new URL("file:///C:/home/user/Documents")),
+    "",
+  );
 });

path/posix/extname.ts

@@ -4,6 +4,7 @@
 import { CHAR_DOT } from "../_common/constants.ts";
 import { assertPath } from "../_common/assert_path.ts";
 import { isPosixPathSeparator } from "./_util.ts";
+import { fromFileUrl } from "./from_file_url.ts";
 
 /**
  * Return the extension of the `path` with leading period.
@@ -18,26 +19,37 @@ import { isPosixPathSeparator } from "./_util.ts";
  * assertEquals(extname("/home/user/Documents/image.png"), ".png");
  * ```
  *
- * @example Working with URLs
+ * @param path The path to get the extension from.
+ * @returns The extension (ex. for `file.ts` returns `.ts`).
+ */
+export function extname(path: string): string;
+/**
+ * Return the extension of the `path` with leading period.
  *
- * Note: This function doesn't automatically strip hash and query parts from
- * URLs. If your URL contains a hash or query, remove them before passing the
- * URL to the function. This can be done by passing the URL to `new URL(url)`,
- * and setting the `hash` and `search` properties to empty strings.
+ * Note: Hashes and query parameters are ignore when constructing a URL.
+ *
+ * @experimental **UNSTABLE**: New API, yet to be vetted.
+ *
+ * @example Usage
  *
  * ```ts
  * import { extname } from "@std/path/posix/extname";
  * import { assertEquals } from "@std/assert";
  *
- * assertEquals(extname("https://deno.land/std/path/mod.ts"), ".ts");
- * assertEquals(extname("https://deno.land/std/path/mod.ts?a=b"), ".ts?a=b");
- * assertEquals(extname("https://deno.land/std/path/mod.ts#header"), ".ts#header");
+ * assertEquals(extname(new URL("file:///home/user/Documents/file.ts")), ".ts");
+ * assertEquals(extname(new URL("file:///home/user/Documents/file.ts?a=b")), ".ts");
+ * assertEquals(extname(new URL("file:///home/user/Documents/file.ts#header")), ".ts");
  * ```
  *
  * @param path The path to get the extension from.
  * @returns The extension (ex. for `file.ts` returns `.ts`).
  */
-export function extname(path: string): string {
+export function extname(path: URL): string;
+export function extname(path: string | URL): string {
+  if (path instanceof URL) {
+    path = fromFileUrl(path);
+  }
+
   assertPath(path);
 
   let startDot = -1;

path/windows/extname.ts

@@ -4,6 +4,7 @@
 import { CHAR_COLON, CHAR_DOT } from "../_common/constants.ts";
 import { assertPath } from "../_common/assert_path.ts";
 import { isPathSeparator, isWindowsDeviceRoot } from "./_util.ts";
+import { fromFileUrl } from "./from_file_url.ts";
 
 /**
  * Return the extension of the `path` with leading period.
@@ -20,7 +21,29 @@ import { isPathSeparator, isWindowsDeviceRoot } from "./_util.ts";
  * @param path The path to get the extension from.
  * @returns The extension of the `path`.
  */
-export function extname(path: string): string {
+export function extname(path: string): string;
+/**
+ * Return the extension of the `path` with leading period.
+ *
+ * @experimental **UNSTABLE**: New API, yet to be vetted.
+ *
+ * @example Usage
+ * ```ts
+ * import { extname } from "@std/path/windows/extname";
+ * import { assertEquals } from "@std/assert";
+ *
+ * const ext = extname(new URL("file:///C:/foo/bar/baz.ext"));
+ * assertEquals(ext, ".ext");
+ * ```
+ *
+ * @param path The path to get the extension from.
+ * @returns The extension of the `path`.
+ */
+export function extname(path: URL): string;
+export function extname(path: string | URL): string {
+  if (path instanceof URL) {
+    path = fromFileUrl(path);
+  }
   assertPath(path);
 
   let start = 0;