Update

path.js

@@ -1,23 +1,3 @@
-/**
- * Takes a url and `URL` properties and returns a new, merged `URL` object.
- * ```js
- * mergeUrl(new URL("https://example.com"))({ port: "8888", username: "joe" })
- * ```
- * @typedef {Partial<Omit<URL, "origin" | "searchParams">>} UrlProperties
- * @param {string|URL} baseUrl
- * @returns {(partialUrl:UrlProperties) => URL}
- */
-export function mergeUrl(baseUrl) {
-  // NOT: Don't mutate the passed url object.
-  const url = new URL(baseUrl instanceof URL ? baseUrl.href : baseUrl);
-  return (urlOrProps) => {
-    Object.entries(urlOrProps).forEach(([key, value]) => {
-      /**@type {any}*/ (url)[key] = value;
-    });
-    return url;
-  };
-}
-
 /**
  * importMetaResolve.
  * @param {string} moduleUrl

response.js

@@ -1,3 +1,4 @@
+import { mergeUrl } from "./url.js";
 /**
  * Creates a new Response object by copying the body and headers from an existing Response object.
  * Difference between cloning and copying of a `Response`:
@@ -36,3 +37,19 @@ export function getResponseBody(input) {
     return JSON.stringify(input);
   }
 }
+
+/**
+ * Fetches a resource based on the provided request, and optionally modifies
+ * the URL using given properties, then copies the response.
+ *
+ * @typedef {import("./url.js").UrlProperties} UrlProperties
+ * @param {Request} request - The original request object.
+ * @param {UrlProperties} [urlOrProps] - Optional properties to modify the request URL.
+ * @returns {Promise<Response>} The copied response.
+ */
+export async function fetchAndCopy(request, urlOrProps) {
+  const url = urlOrProps ? mergeUrl(request.url)(urlOrProps) : request.url;
+  const newRequest = new Request(url, request);
+  const response = await fetch(newRequest);
+  return copyResponse(response);
+}

url.js

@@ -73,3 +73,23 @@ export function appendSearchParams(url) {
     return urlObject;
   };
 }
+
+/**
+ * Takes a url and `URL` properties and returns a new, merged `URL` object.
+ * ```js
+ * mergeUrl(new URL("https://example.com"))({ port: "8888", username: "joe" })
+ * ```
+ * @typedef {Partial<Omit<URL, "origin" | "searchParams">>} UrlProperties
+ * @param {string|URL} baseUrl
+ * @returns {(partialUrl:UrlProperties) => URL}
+ */
+export function mergeUrl(baseUrl) {
+  // NOT: Don't mutate the passed url object.
+  const url = new URL(baseUrl instanceof URL ? baseUrl.href : baseUrl);
+  return (urlOrProps) => {
+    Object.entries(urlOrProps).forEach(([key, value]) => {
+      /**@type {any}*/ (url)[key] = value;
+    });
+    return url;
+  };
+}