even better ssr caching

src/server/create-renderer.js

@@ -36,8 +36,12 @@ export function createRenderer ({
     ): void {
       let result = ''
       let stackDepth = 0
-      const write = (str: string, next: Function) => {
-        result += str
+
+      const write = (text: string, next: Function) => {
+        if (write.caching && text) {
+          write.buffer += text
+        }
+        result += text
         if (stackDepth >= MAX_STACK_DEPTH) {
           process.nextTick(() => {
             try { next() } catch (e) {
@@ -50,6 +54,9 @@ export function createRenderer ({
           stackDepth--
         }
       }
+      write.caching = false
+      write.buffer = ''
+
       try {
         render(component, write, () => {
           done(null, result)

src/server/render-stream.js

@@ -25,7 +25,10 @@ export default class RenderStream extends stream.Readable {
     this.expectedSize = 0
     this.stackDepth = 0
 
-    this.write = (text: string, next: Function) => {
+    const write = this.write = (text: string, next: Function) => {
+      if (write.caching && text) {
+        write.buffer += text
+      }
       const n = this.expectedSize
       this.buffer += text
       if (this.buffer.length >= n) {
@@ -47,6 +50,8 @@ export default class RenderStream extends stream.Readable {
         }
       }
     }
+    write.caching = false
+    write.buffer = ''
 
     this.end = () => {
       // the rendering is finished; we should push out the last of the buffer.

src/server/render.js

@@ -25,9 +25,28 @@ export function createRenderFunction (
     isRoot: boolean
   ) {
     if (node.componentOptions) {
-      const child =
-        getCachedComponent(node) ||
-        createComponentInstanceForVnode(node)._render()
+      // check cache hit
+      const Ctor = node.componentOptions.Ctor
+      const getKey = Ctor.options.server && Ctor.options.server.getCacheKey
+      if (getKey) {
+        const key = Ctor.cid + '::' + getKey(node.componentOptions.propsData)
+        if (cache.has(key)) {
+          return write(cache.get(key), next)
+        } else {
+          if (!write.caching) {
+            // initialize if not already caching
+            write.caching = true
+            const _next = next
+            next = () => {
+              cache.set(key, write.buffer)
+              write.caching = false
+              write.buffer = ''
+              _next()
+            }
+          }
+        }
+      }
+      const child = createComponentInstanceForVnode(node)._render()
       child.parent = node
       renderNode(child, write, next, isRoot)
     } else {
@@ -39,21 +58,6 @@ export function createRenderFunction (
     }
   }
 
-  function getCachedComponent (node) {
-    const Ctor = node.componentOptions.Ctor
-    const getKey = Ctor.options.server && Ctor.options.server.getCacheKey
-    if (getKey) {
-      const key = Ctor.cid + '::' + getKey(node.componentOptions.propsData)
-      if (cache.has(key)) {
-        return cache.get(key)
-      } else {
-        const res = createComponentInstanceForVnode(node)._render()
-        cache.set(key, res)
-        return res
-      }
-    }
-  }
-
   function renderElement (
     el: VNode,
     write: Function,
@@ -94,9 +98,6 @@ export function createRenderFunction (
   }
 
   function renderStartingTag (node: VNode) {
-    if (node._rendered) {
-      return node._rendered
-    }
     let markup = `<${node.tag}`
     if (node.data) {
       // check directives
@@ -124,14 +125,13 @@ export function createRenderFunction (
     if (node.host && (scopeId = node.host.$options._scopeId)) {
       markup += ` ${scopeId}`
     }
-    let _node = node
-    while (_node) {
-      if ((scopeId = _node.context.$options._scopeId)) {
+    while (node) {
+      if ((scopeId = node.context.$options._scopeId)) {
         markup += ` ${scopeId}`
       }
-      _node = _node.parent
+      node = node.parent
     }
-    return (node._rendered = markup + '>')
+    return markup + '>'
   }
 
   return function render (