fix: stop middleware when writableEnded flag is set

Author: pi0

src/app.ts

@@ -21,6 +21,10 @@ export function createApp (): App {
 
       const val = await layer.handle(req, res)
 
+      if (res.writableEnded) {
+        break
+      }
+
       const type = typeof val
       if (type === 'string') {
         send(res, val, MIMES.html)

test/fixture/server.js

@@ -14,6 +14,7 @@ const app = createApp()
 
 app.use('/api/hello', req => ({ url: req.url }))
 app.use('/api/express', createExpress())
+app.use('/api', (_req, res) => { res.end('API root') })
 app.use('/', () => 'Hello world!')
 
 const port = process.env.PORT || 3000