From 7b72ec6ec2a30d8a3e1eb1fa501cfa55e7870d64 Mon Sep 17 00:00:00 2001
From: dario <dario.bugmann@outlook.com>
Date: Mon, 2 Jun 2025 17:47:51 +0200
Subject: [PATCH 1/2] fix readable stream as body check on safari

---
 src/utils.ts | 44 +++++++++++++++-----------------------------
 1 file changed, 15 insertions(+), 29 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index b2685f1..053ed45 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -85,34 +85,20 @@ function createMultipartStream(entries: readonly MultipartEntry[]): MultipartFor
   };
 }
 
-async function detectStreamSupport(): Promise<boolean> {
-  try {
-    const testStream = new ReadableStream({
-      start(controller) {
-        controller.enqueue(new Uint8Array([0])); // Minimal stream chunk
-        controller.close();
-      },
-    });
-
-    const request = new Request('data:text/plain;charset=utf-8,42', {
-      method: 'POST',
-      body: testStream,
-      // Required for streaming request body in some browsers,
-      // or it will fail and assume it's not supported
-      // @ts-ignore
-      duplex: 'half',
-    });
-
-    // If fails to handle fetch(Request), it's likely not a native implementation of
-    // Fetch API, so it's not supported.
-    await fetch(request.clone());
-
-    const body = await request.text();
-    // if different from '\x00', it's likely not supported
-    return body === '\x00';
-  } catch {
-    return false;
-  }
+function detectStreamSupport()  {
+  let duplexAccessed = false;
+
+  const hasContentType = new Request('data:text/plain;charset=utf-8,42', {
+    body: new ReadableStream(),
+    method: 'POST',
+    // @ts-ignore
+    get duplex() {
+      duplexAccessed = true;
+      return 'half';
+    },
+  }).headers.has('Content-Type');
+
+  return duplexAccessed && !hasContentType;
 }
 
 function createFormData(entries: readonly MultipartEntry[]): FormData {
@@ -163,7 +149,7 @@ export async function createMultipartRequestInit(
   method: 'POST' | 'PUT',
   entries: readonly MultipartEntry[],
 ): Promise<RequestInit> {
-  if (await detectStreamSupport()) {
+  if (detectStreamSupport()) {
     const { stream, boundary } = createMultipartStream(entries);
 
     return {

From 8f17913895b626d2fc37ac04144e38cffa2229cb Mon Sep 17 00:00:00 2001
From: Dario Bugmann <dario.bugmann@outlook.com>
Date: Wed, 4 Jun 2025 07:08:28 +0200
Subject: [PATCH 2/2] add fetch call again to detect non-native 'fetch' envs
 and remove data url in the support check

---
 src/utils.ts | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index 053ed45..a70ddc9 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -85,20 +85,35 @@ function createMultipartStream(entries: readonly MultipartEntry[]): MultipartFor
   };
 }
 
-function detectStreamSupport()  {
-  let duplexAccessed = false;
-
-  const hasContentType = new Request('data:text/plain;charset=utf-8,42', {
-    body: new ReadableStream(),
-    method: 'POST',
-    // @ts-ignore
-    get duplex() {
-      duplexAccessed = true;
-      return 'half';
-    },
-  }).headers.has('Content-Type');
-
-  return duplexAccessed && !hasContentType;
+async function detectStreamSupport() {
+  try {
+    let duplexAccessed = false;
+    const hasContentType = new Request('https://', {
+      body: new ReadableStream(),
+      method: 'POST',
+      // @ts-ignore
+      get duplex() {
+        duplexAccessed = true;
+        return 'half';
+      },
+    }).headers.has('Content-Type');
+
+    // If fails to handle fetch(Request), it's likely not a native implementation of
+    // Fetch API, so it's not supported.
+    const res = await fetch(
+      new Request('data:text/plain;charset=utf-8,42', {
+        method: 'POST',
+        body: new ReadableStream(),
+        // @ts-ignore
+        duplex: 'half',
+      }),
+    );
+    const body = await res.text();
+
+    return duplexAccessed && !hasContentType && body === '\x00';
+  } catch (error) {
+    return false;
+  }
 }
 
 function createFormData(entries: readonly MultipartEntry[]): FormData {
@@ -149,7 +164,7 @@ export async function createMultipartRequestInit(
   method: 'POST' | 'PUT',
   entries: readonly MultipartEntry[],
 ): Promise<RequestInit> {
-  if (detectStreamSupport()) {
+  if (await detectStreamSupport()) {
     const { stream, boundary } = createMultipartStream(entries);
 
     return {