refactor(server-renderer): adjust streaming API

- add `pipeToNodeWritable`
- add `pipeToWebWritable`

packages/server-renderer/__tests__/webStream.spec.ts

@@ -3,10 +3,19 @@
  */
 
 import { createApp, h, defineAsyncComponent } from 'vue'
-import { ReadableStream } from 'stream/web'
-import { renderToWebStream } from '../src'
+import { ReadableStream, TransformStream } from 'stream/web'
+import { pipeToWebWritable, renderToWebStream } from '../src'
 
-test('should work', async () => {
+beforeEach(() => {
+  global.ReadableStream = ReadableStream
+})
+
+afterEach(() => {
+  // @ts-ignore
+  delete global.ReadableStream
+})
+
+test('renderToWebStream', async () => {
   const Async = defineAsyncComponent(() =>
     Promise.resolve({
       render: () => h('div', 'async')
@@ -16,14 +25,42 @@ test('should work', async () => {
     render: () => [h('div', 'parent'), h(Async)]
   }
 
-  const stream = renderToWebStream(createApp(App), {}, ReadableStream)
+  const stream = renderToWebStream(createApp(App))
 
   const reader = stream.getReader()
+  const decoder = new TextDecoder()
 
   let res = ''
   await reader.read().then(function read({ done, value }): any {
     if (!done) {
-      res += value
+      res += decoder.decode(value)
+      return reader.read().then(read)
+    }
+  })
+
+  expect(res).toBe(`<!--[--><div>parent</div><div>async</div><!--]-->`)
+})
+
+test('pipeToWebWritable', async () => {
+  const Async = defineAsyncComponent(() =>
+    Promise.resolve({
+      render: () => h('div', 'async')
+    })
+  )
+  const App = {
+    render: () => [h('div', 'parent'), h(Async)]
+  }
+
+  const { readable, writable } = new TransformStream()
+  pipeToWebWritable(createApp(App), {}, writable)
+
+  const reader = readable.getReader()
+  const decoder = new TextDecoder()
+
+  let res = ''
+  await reader.read().then(function read({ done, value }): any {
+    if (!done) {
+      res += decoder.decode(value)
       return reader.read().then(read)
     }
   })