From 766d7d5fe44b9b0dacb012f5c0aafd0d1a66c9a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A1r=20=C3=96rlygsson?= <mar.nospam@anomy.net>
Date: Tue, 20 Nov 2018 14:53:28 +0000
Subject: [PATCH] Run initializeStore() only once per route on server (#5644)

On the server `props.initialMobxState` received by the `constructor` is a fully functioning mobx store that was instantiated by `getInitialProps()` only a few ticks earlier.
Thus, creating a new instance is unneccessary.

In the browser, however, `props.initialMobxState` is a hydrated plain object and thus the store needs to be initialized.
---
 examples/with-mobx/pages/_app.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/examples/with-mobx/pages/_app.js b/examples/with-mobx/pages/_app.js
index d8c59b13..32921ffd 100644
--- a/examples/with-mobx/pages/_app.js
+++ b/examples/with-mobx/pages/_app.js
@@ -21,7 +21,10 @@ class MyMobxApp extends App {
 
     constructor(props) {
         super(props)
-        this.mobxStore = initializeStore(props.initialMobxState)
+        const isServer = typeof window === 'undefined'
+        this.mobxStore = isServer ?
+            props.initialMobxState:
+            initializeStore(props.initialMobxState)
     }
 
     render() {