fix: Allow ArrayBuffer as Fetch request body (#5831)

2 files changed, 15 insertions, 0 deletions

diff --git a/cli/js/web/fetch.ts b/cli/js/web/fetch.ts
index 3485a770a..9054465bf 100644
--- a/cli/js/web/fetch.ts
+++ b/cli/js/web/fetch.ts
@@ -505,6 +505,8 @@ export async function fetch(
           contentType = "text/plain;charset=UTF-8";
         } else if (isTypedArray(init.body)) {
           body = init.body;
+        } else if (init.body instanceof ArrayBuffer) {
+          body = new Uint8Array(init.body);
         } else if (init.body instanceof URLSearchParams) {
           body = new TextEncoder().encode(init.body.toString());
           contentType = "application/x-www-form-urlencoded;charset=UTF-8";
diff --git a/cli/tests/unit/fetch_test.ts b/cli/tests/unit/fetch_test.ts
index 458c34ae2..db4c3a407 100644
--- a/cli/tests/unit/fetch_test.ts
+++ b/cli/tests/unit/fetch_test.ts
@@ -260,6 +260,19 @@ unitTest(
 
 unitTest(
   { perms: { net: true } },
+  async function fetchInitArrayBufferBody(): Promise<void> {
+    const data = "Hello World";
+    const response = await fetch("http://localhost:4545/echo_server", {
+      method: "POST",
+      body: new TextEncoder().encode(data).buffer,
+    });
+    const text = await response.text();
+    assertEquals(text, data);
+  }
+);
+
+unitTest(
+  { perms: { net: true } },
   async function fetchInitURLSearchParamsBody(): Promise<void> {
     const data = "param1=value1&param2=value2";
     const params = new URLSearchParams(data);