From d69a02486d1f714fa6cf78d55f38a26ae35a5d2a Mon Sep 17 00:00:00 2001
From: Yarchik <spoko.dev@gmail.com>
Date: Thu, 2 Jul 2026 00:46:56 +0100
Subject: [PATCH] fix(response): keep the Blob content type instead of forcing
 octet-stream

Assigning a Blob to ctx.body forced Content-Type: application/octet-stream
and ignored the Blob's own type. A typed Blob such as
new Blob(data, { type: 'image/png' }) was sent with the wrong content type,
so browsers download the payload instead of rendering it. The Response body
path already copies the body's own Content-Type, and the original feature
request (#1777) specified ctx.type = blob.type.

Use val.type when present and fall back to application/octet-stream for an
untyped Blob. An explicitly preset Content-Type still wins.
---
 __tests__/response/body.test.js | 13 +++++++++++++
 lib/response.js                 |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/__tests__/response/body.test.js b/__tests__/response/body.test.js
index c63cb4d75..239a77689 100644
--- a/__tests__/response/body.test.js
+++ b/__tests__/response/body.test.js
@@ -302,6 +302,19 @@ describe('res.body=', () => {
       res.body = new Blob([new Uint8Array([1, 2, 3])], { type: 'application/octet-stream' })
       assert.strictEqual(3, res.header['content-length'])
     })
+
+    it('should keep the Blob content type', () => {
+      const res = response()
+      res.body = new Blob([new Uint8Array([1, 2, 3])], { type: 'image/png' })
+      assert.strictEqual('image/png', res.header['content-type'])
+    })
+
+    it('should not override an explicit content type', () => {
+      const res = response()
+      res.type = 'application/json'
+      res.body = new Blob(['x'], { type: 'image/png' })
+      assert.strictEqual('application/json; charset=utf-8', res.header['content-type'])
+    })
   })
 
   describe('when a response is given', () => {
diff --git a/lib/response.js b/lib/response.js
index 9b6741476..275706e46 100644
--- a/lib/response.js
+++ b/lib/response.js
@@ -207,7 +207,7 @@ module.exports = {
 
     // blob
     if (val instanceof Blob) {
-      if (setType) this.type = 'bin'
+      if (setType) this.type = val.type || 'bin'
       this.length = val.size
       cleanupPreviousStream()
       return