feat(dev-server): support streaming (#19)

packages/dev-server/package.json

@@ -44,6 +44,7 @@
     "bumpp": "^9.2.0",
     "glob": "^10.3.4",
     "hono": "^3.5.8",
+    "playwright": "^1.39.0",
     "publint": "^0.1.12",
     "rimraf": "^5.0.1",
     "tsup": "^7.2.0",
@@ -57,4 +58,4 @@
     "@hono/node-server": "^1.2.0",
     "miniflare": "^3.20231016.0"
   }
-}
+}

packages/dev-server/src/dev-server.ts

@@ -95,18 +95,10 @@ export function devServer(options?: DevServerOptions): Plugin {
             })
             if (
               options?.injectClientScript !== false &&
-              // If the response is a streaming, it does not inject the script:
-              !response.headers.get('transfer-encoding')?.match('chunked') &&
               response.headers.get('content-type')?.match(/^text\/html/)
             ) {
-              const body =
-                (await response.text()) + '<script type="module" src="/@vite/client"></script>'
-              const headers = new Headers(response.headers)
-              headers.delete('content-length')
-              return new Response(body, {
-                status: response.status,
-                headers,
-              })
+              const script = '<script>import("/@vite/client")</script>'
+              return injectStringToResponse(response, script)
             }
             return response
           })(req, res)
@@ -118,3 +110,49 @@ export function devServer(options?: DevServerOptions): Plugin {
   }
   return plugin
 }
+
+function injectStringToResponse(response: Response, content: string) {
+  const stream = response.body
+  const newContent = new TextEncoder().encode(content)
+
+  if (!stream) return null
+
+  const reader = stream.getReader()
+  const newContentReader = new ReadableStream({
+    start(controller) {
+      controller.enqueue(newContent)
+      controller.close()
+    },
+  }).getReader()
+
+  const combinedStream = new ReadableStream({
+    async start(controller) {
+      for (;;) {
+        const [existingResult, newContentResult] = await Promise.all([
+          reader.read(),
+          newContentReader.read(),
+        ])
+
+        if (existingResult.done && newContentResult.done) {
+          controller.close()
+          break
+        }
+
+        if (!existingResult.done) {
+          controller.enqueue(existingResult.value)
+        }
+        if (!newContentResult.done) {
+          controller.enqueue(newContentResult.value)
+        }
+      }
+    },
+  })
+
+  const headers = new Headers(response.headers)
+  headers.delete('content-length')
+
+  return new Response(combinedStream, {
+    headers,
+    status: response.status,
+  })
+}

packages/dev-server/test/e2e.test.ts

@@ -4,7 +4,10 @@ test('Should return 200 response', async ({ page }) => {
   const response = await page.goto('/')
   expect(response?.status()).toBe(200)
 
-  const content = await page.textContent('body')
+  const headers = response?.headers() ?? {}
+  expect(headers['x-via']).toBe('vite')
+
+  const content = await page.textContent('h1')
   expect(content).toBe('Hello Vite!')
 })
 
@@ -14,26 +17,23 @@ test('Should contain an injected script tag', async ({ page }) => {
   const lastScriptTag = await page.$('script:last-of-type')
   expect(lastScriptTag).not.toBeNull()
 
-  const typeValue = await lastScriptTag?.getAttribute('type')
-  expect(typeValue).toBe('module')
-
-  const srcValue = await lastScriptTag?.getAttribute('src')
-  expect(srcValue).toBe('/@vite/client')
+  const content = await lastScriptTag?.textContent()
+  expect(content).toBe('import("/@vite/client")')
 })
 
 test('Should have Cloudflare bindings', async ({ page }) => {
   const response = await page.goto('/name')
   expect(response?.status()).toBe(200)
 
-  const content = await page.textContent('body')
+  const content = await page.textContent('h1')
   expect(content).toBe('My name is Hono')
 })
 
 test('Should not throw an error if using `waitUntil`', async ({ page }) => {
   const response = await page.goto('/wait-until')
   expect(response?.status()).toBe(200)
 
-  const content = await page.textContent('body')
+  const content = await page.textContent('h1')
   expect(content).toBe('Hello Vite!')
 })
 
@@ -53,3 +53,14 @@ test('Should exclude the file specified in the config file', async ({ page }) =>
   response = await page.goto('/static/foo.png')
   expect(response?.status()).toBe(404)
 })
+
+test('Should return 200 response - /stream', async ({ page }) => {
+  const response = await page.goto('/stream')
+  expect(response?.status()).toBe(200)
+
+  const headers = response?.headers() ?? {}
+  expect(headers['x-via']).toBe('vite')
+
+  const content = await page.textContent('h1')
+  expect(content).toBe('Hello Vite!')
+})

packages/dev-server/test/mock/worker.ts

@@ -6,27 +6,50 @@ const app = new Hono<{
   }
 }>()
 
-app.get('/', (c) => c.html('<h1>Hello Vite!</h1>'))
+app.get('/', (c) => {
+  c.header('x-via', 'vite')
+  return c.html('<h1>Hello Vite!</h1>')
+})
+
 app.get('/name', (c) => c.html(`<h1>My name is ${c.env.NAME}</h1>`))
+
 app.get('/wait-until', (c) => {
   const fn = async () => {}
   c.executionCtx.waitUntil(fn())
   return c.html('<h1>Hello Vite!</h1>')
 })
+
 app.get('/file.ts', (c) => {
   return c.text('console.log("exclude me!")')
 })
+
 app.get('/app/foo', (c) => {
   return c.html('<h1>exclude me!</h1>')
 })
+
 app.get('/ends-in-ts', (c) => {
   return c.text('this should not be excluded')
 })
+
 app.get('/favicon.ico', (c) => {
   return c.text('a good favicon')
 })
+
 app.get('/static/foo.png', (c) => {
   return c.text('a good image')
 })
 
+app.get('/stream', () => {
+  const html = new TextEncoder().encode('<h1>Hello Vite!</h1>')
+  const stream = new ReadableStream({
+    start(controller) {
+      controller.enqueue(html)
+      controller.close()
+    },
+  })
+  return new Response(stream, {
+    headers: { 'Content-Type': 'text/html', 'x-via': 'vite' },
+  })
+})
+
 export default app

yarn.lock

@@ -283,6 +283,7 @@ __metadata:
     glob: ^10.3.4
     hono: ^3.5.8
     miniflare: ^3.20231016.0
+    playwright: ^1.39.0
     publint: ^0.1.12
     rimraf: ^5.0.1
     tsup: ^7.2.0
@@ -3546,7 +3547,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"playwright@npm:1.39.0":
+"playwright@npm:1.39.0, playwright@npm:^1.39.0":
   version: 1.39.0
   resolution: "playwright@npm:1.39.0"
   dependencies: