From 0b3db9173174c7b6ee5e1180441c34d43723982d Mon Sep 17 00:00:00 2001
From: Naoyuki Kanezawa <naoyuki.kanezawa@gmail.com>
Date: Thu, 26 Jan 2017 20:06:50 +0900
Subject: [PATCH] Fix handling finished response (#889)

* allows to not return props if response is already finished on getInitialProps

* check res.finished after getInitialProps call of Document
---
 lib/utils.js     | 2 +-
 server/render.js | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/utils.js b/lib/utils.js
index 56047419062a5..b1757f9878496 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -46,7 +46,7 @@ export async function loadGetInitialProps (Component, ctx) {
   if (!Component.getInitialProps) return {}
 
   const props = await Component.getInitialProps(ctx)
-  if (!props) {
+  if (!props && (!ctx.res || !ctx.res.finished)) {
     const compName = Component.displayName || Component.name
     const message = `"${compName}.getInitialProps()" should resolve to an object. But found "${props}" instead.`
     throw new Error(message)
diff --git a/server/render.js b/server/render.js
index 901b21b8b12b0..edee8c1149582 100644
--- a/server/render.js
+++ b/server/render.js
@@ -83,6 +83,8 @@ async function doRender (req, res, pathname, query, {
 
   const docProps = await loadGetInitialProps(Document, { ...ctx, renderPage })
 
+  if (res.finished) return
+
   const doc = createElement(Document, {
     __NEXT_DATA__: {
       component,