fix(context): set the values of already set (#834)

deno_dist/context.ts

@@ -65,6 +65,11 @@ export class Context<
   }
 
   set res(_res: Response) {
+    if (this._res) {
+      this._res.headers.forEach((v, k) => {
+        _res.headers.set(k, v)
+      })
+    }
     this._res = _res
     this.finalized = true
   }

src/context.test.ts

@@ -121,6 +121,14 @@ describe('Context', () => {
     expect(c.res.status).toBe(201)
   })
 
+  it('Should append the previous headers to new Response', () => {
+    c.res.headers.set('x-Custom1', 'Message1')
+    const res2 = new Response('foo2')
+    res2.headers.set('x-Custom2', 'Message2')
+    c.res = res2
+    expect(c.res.headers.get('x-Custom1')).toBe('Message1')
+  })
+
   it('Should return 200 response', async () => {
     const res = c.text('Text')
     expect(res.status).toBe(200)

src/context.ts

@@ -65,6 +65,11 @@ export class Context<
   }
 
   set res(_res: Response) {
+    if (this._res) {
+      this._res.headers.forEach((v, k) => {
+        _res.headers.set(k, v)
+      })
+    }
     this._res = _res
     this.finalized = true
   }

src/middleware/cors/index.test.ts

@@ -31,6 +31,8 @@ describe('CORS by Middleware', () => {
     })
   )
 
+  app.use('/api5/*', cors())
+
   app.get('/api/abc', (c) => {
     return c.json({ success: true })
   })
@@ -43,6 +45,9 @@ describe('CORS by Middleware', () => {
   app.get('/api4/abc', (c) => {
     return c.json({ success: true })
   })
+  app.get('/api5/abc', () => {
+    return new Response(JSON.stringify({ success: true }))
+  })
 
   it('GET default', async () => {
     const res = await app.request('http://localhost/api/abc')
@@ -130,4 +135,11 @@ describe('CORS by Middleware', () => {
     res = await app.request(req)
     expect(res.headers.get('Access-Control-Allow-Origin')).toBe('http://example.com')
   })
+
+  it('With raw Response object', async () => {
+    const res = await app.request('http://localhost/api5/abc')
+
+    expect(res.headers.get('Access-Control-Allow-Origin')).toBe('*')
+    expect(res.headers.get('Vary')).toBeNull()
+  })
 })