tweak render stream implementation

src/server/render-stream.js

@@ -1,6 +1,6 @@
 import stream from 'stream'
 
-const MAX_STACK_DEPTH = 500
+const MAX_STACK_DEPTH = 1000
 
 /**
  * Original RenderStream implmentation by Sasha Aickin (@aickin)
@@ -12,35 +12,14 @@ export default class RenderStream extends stream.Readable {
     super()
     this.buffer = ''
     this.render = render
-  }
+    this.expectedSize = 0
 
-  _read (n) {
-    let bufferToPush
-    // it's possible that the last chunk added bumped the buffer up to > 2 * n,
-    // which means we will need to go through multiple read calls to drain it
-    // down to < n.
-    if (this.done) {
-      this.push(null)
-      return
-    }
-    if (this.buffer.length >= n) {
-      bufferToPush = this.buffer.substring(0, n)
-      this.buffer = this.buffer.substring(n)
-      this.push(bufferToPush)
-      return
-    }
-    if (!this.next) {
-      this.stackDepth = 0
-      // start the rendering chain.
-      this.render(
-        // write
-        (text, next) => {
+    this.write = (text, next) => {
+      const n = this.expectedSize
       this.buffer += text
       if (this.buffer.length >= n) {
         this.next = next
-            bufferToPush = this.buffer.substring(0, n)
-            this.buffer = this.buffer.substring(n)
-            this.push(bufferToPush)
+        this.pushBySize(n)
       } else {
         // continue rendering until we have enough text to call this.push().
         // sometimes do this as process.nextTick to get out of stack overflows.
@@ -52,13 +31,38 @@ export default class RenderStream extends stream.Readable {
           this.stackDepth--
         }
       }
-        },
-        // done
-        () => {
+    }
+
+    this.end = () => {
       // the rendering is finished; we should push out the last of the buffer.
       this.done = true
       this.push(this.buffer)
-        })
+    }
+  }
+
+  pushBySize (n) {
+    const bufferToPush = this.buffer.substring(0, n)
+    this.buffer = this.buffer.substring(n)
+    this.push(bufferToPush)
+  }
+
+  _read (n) {
+    this.expectedSize = n
+    // it's possible that the last chunk added bumped the buffer up to > 2 * n,
+    // which means we will need to go through multiple read calls to drain it
+    // down to < n.
+    if (this.done) {
+      this.push(null)
+      return
+    }
+    if (this.buffer.length >= n) {
+      this.pushBySize(n)
+      return
+    }
+    if (!this.next) {
+      this.stackDepth = 0
+      // start the rendering chain.
+      this.render(this.write, this.end)
     } else {
       // continue with the rendering.
       this.next()