From c0aea90a3f608108d10d0306ecc165c27a78ad22 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eduardo=20Bou=C3=A7as?= <mail@eduardoboucas.com>
Date: Wed, 15 Oct 2025 09:27:25 +0100
Subject: [PATCH 1/2] feat: add `fetch` parameter to `fetchWithCache`

---
 packages/cache/src/fetchwithcache.test.ts | 21 +++++++++++++++++++++
 packages/cache/src/fetchwithcache.ts      |  7 +++++++
 2 files changed, 28 insertions(+)

diff --git a/packages/cache/src/fetchwithcache.test.ts b/packages/cache/src/fetchwithcache.test.ts
index 555c712c..165abbd3 100644
--- a/packages/cache/src/fetchwithcache.test.ts
+++ b/packages/cache/src/fetchwithcache.test.ts
@@ -307,4 +307,25 @@ describe('`fetchWithCache`', () => {
     mockFetch.restore()
     expect(mockFetch.fulfilled).toBe(true)
   })
+
+  test('Accepts a custom `fetch` implementation', async () => {
+    const mockFetch = new MockFetch()
+      .get({
+        url: 'https://example.netlify/.netlify/cache/https%3A%2F%2Fnetlify.com%2F',
+        response: new Response(null, { status: 404 }),
+      })
+      .post({
+        url: 'https://example.netlify/.netlify/cache/https%3A%2F%2Fnetlify.com%2F',
+        response: new Response(null, { status: 201 }),
+      })
+      .inject()
+    const body = 'Hello from custom fetch'
+    const customFetch: typeof globalThis.fetch = async () => new Response(body)
+
+    const response = await fetchWithCache('https://netlify.com', { fetch: customFetch })
+    expect(await response.text()).toBe(body)
+
+    mockFetch.restore()
+    expect(mockFetch.fulfilled).toBe(true)
+  })
 })
diff --git a/packages/cache/src/fetchwithcache.ts b/packages/cache/src/fetchwithcache.ts
index 77f7b3f4..ae50c6fa 100644
--- a/packages/cache/src/fetchwithcache.ts
+++ b/packages/cache/src/fetchwithcache.ts
@@ -31,6 +31,11 @@ type CacheOptions = CacheSettings & {
    */
   cache?: NetlifyCache | string
 
+  /**
+   * A custom `fetch` implementation to be used instead of the native one.
+   */
+  fetch?: typeof globalThis.fetch
+
   /**
    * When `fetchWithCache` fetches a new response and adds it to the cache, the
    * `Promise` it returns waits for both the network call to finish and for the
@@ -115,6 +120,8 @@ export const fetchWithCache: FetchWithCache = async (
     return cached
   }
 
+  const { fetch = globalThis.fetch } = cacheOptions
+
   const fresh = await fetch(request)
   if (!fresh.body) {
     return fresh

From d836a04b514a269d136c7e45b6df23ec7a59524d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eduardo=20Bou=C3=A7as?= <mail@eduardoboucas.com>
Date: Wed, 15 Oct 2025 09:33:37 +0100
Subject: [PATCH 2/2] chore: update test

---
 packages/cache/src/fetchwithcache.test.ts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/packages/cache/src/fetchwithcache.test.ts b/packages/cache/src/fetchwithcache.test.ts
index 165abbd3..4062fe48 100644
--- a/packages/cache/src/fetchwithcache.test.ts
+++ b/packages/cache/src/fetchwithcache.test.ts
@@ -319,11 +319,10 @@ describe('`fetchWithCache`', () => {
         response: new Response(null, { status: 201 }),
       })
       .inject()
-    const body = 'Hello from custom fetch'
-    const customFetch: typeof globalThis.fetch = async () => new Response(body)
+    const customFetch: typeof globalThis.fetch = async () => new Response('rijwiel')
 
     const response = await fetchWithCache('https://netlify.com', { fetch: customFetch })
-    expect(await response.text()).toBe(body)
+    expect(await response.text()).toBe('rijwiel')
 
     mockFetch.restore()
     expect(mockFetch.fulfilled).toBe(true)