From 1c44f0eb5fdba3182cf7e7800534c25f6c76fb94 Mon Sep 17 00:00:00 2001
From: Rusta <rustauk@gmail.com>
Date: Tue, 7 Feb 2017 17:28:23 +0000
Subject: [PATCH 1/3] enable custom shouldUpdateScroll function in
 gatsby-browser file

---
 lib/utils/web-entry.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/utils/web-entry.js b/lib/utils/web-entry.js
index 96c749f428e8f..e23c0112b5084 100644
--- a/lib/utils/web-entry.js
+++ b/lib/utils/web-entry.js
@@ -4,7 +4,7 @@ import ReactDOM from 'react-dom'
 import { applyRouterMiddleware, browserHistory, Router } from 'react-router'
 import useScroll from 'react-router-scroll/lib/useScroll'
 import createRoutes from 'create-routes'
-import { onRouteChange, onRouteUpdate, modifyRoutes } from 'gatsby-browser'
+import { onRouteChange, onRouteUpdate, modifyRoutes, customShouldUpdateScroll } from 'gatsby-browser'
 
 const loadContext = require('.gatsby-context')
 
@@ -33,9 +33,13 @@ function onUpdate () {
   }
 }
 
-function shouldUpdateScroll (prevRouterProps, { location: { pathname } }) {
+function shouldUpdateScroll (prevRouterProps, nextRouterProps) {
+  if (customShouldUpdateScroll) {
+    return customShouldUpdateScroll(prevRouterProps, nextRouterProps)
+  }
   if (prevRouterProps) {
     const { location: { pathname: oldPathname } } = prevRouterProps
+    const { location: { pathname } } = nextRouterProps
     if (oldPathname === pathname) {
       return false
     }

From 7f853c8a13e80058cc95121d0f810c4e4f0a8f3d Mon Sep 17 00:00:00 2001
From: Rusta <rustauk@gmail.com>
Date: Tue, 7 Feb 2017 19:05:03 +0000
Subject: [PATCH 2/3] add sensible name for the shouldUpdateScroll API
 function; add details of this override function to the README

---
 README.md              |  2 ++
 lib/utils/web-entry.js | 10 +++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 9d66e912b7e11..f9b4154647cac 100644
--- a/README.md
+++ b/README.md
@@ -334,6 +334,8 @@ files which start with an underscore:
 * (optional) `gatsby-browser.js` - a way to hook into key application events.
   * Export `onRouteUpdate` of type `function()` to be notified whenever React-Router navigates.
   * Export `modifyRoutes` of type `function(routes: Object) => Object` to modify the react-router routes.
+  * Export `shouldUpdateScroll` of type `function(prevRouterProps: Object, nextRouterProps: Object) => boolean`
+  to determine if a given route change should scroll.
 * (optional) `gatsby-node.js` - a way to hook into events during build
 and development.
 
diff --git a/lib/utils/web-entry.js b/lib/utils/web-entry.js
index e23c0112b5084..c9fad5e8be424 100644
--- a/lib/utils/web-entry.js
+++ b/lib/utils/web-entry.js
@@ -4,7 +4,7 @@ import ReactDOM from 'react-dom'
 import { applyRouterMiddleware, browserHistory, Router } from 'react-router'
 import useScroll from 'react-router-scroll/lib/useScroll'
 import createRoutes from 'create-routes'
-import { onRouteChange, onRouteUpdate, modifyRoutes, customShouldUpdateScroll } from 'gatsby-browser'
+import { onRouteChange, onRouteUpdate, modifyRoutes, shouldUpdateScroll } from 'gatsby-browser'
 
 const loadContext = require('.gatsby-context')
 
@@ -33,9 +33,9 @@ function onUpdate () {
   }
 }
 
-function shouldUpdateScroll (prevRouterProps, nextRouterProps) {
-  if (customShouldUpdateScroll) {
-    return customShouldUpdateScroll(prevRouterProps, nextRouterProps)
+function updateScroll (prevRouterProps, nextRouterProps) {
+  if (shouldUpdateScroll) {
+    return shouldUpdateScroll(prevRouterProps, nextRouterProps)
   }
   if (prevRouterProps) {
     const { location: { pathname: oldPathname } } = prevRouterProps
@@ -66,7 +66,7 @@ loadConfig(() =>
       <Router
         history={browserHistory}
         routes={routes}
-        render={applyRouterMiddleware(useScroll(shouldUpdateScroll))}
+        render={applyRouterMiddleware(useScroll(updateScroll))}
         onUpdate={onUpdate}
       />,
       typeof window !== 'undefined' ? document.getElementById('react-mount') : undefined)

From 3693947f3c359f3891d6d5877ee037d5d3bc7c7a Mon Sep 17 00:00:00 2001
From: Rusta <rustauk@gmail.com>
Date: Tue, 7 Feb 2017 19:40:21 +0000
Subject: [PATCH 3/3] rename function to defaultShouldUpdateScroll

---
 lib/utils/web-entry.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/utils/web-entry.js b/lib/utils/web-entry.js
index c9fad5e8be424..46fa2666f4923 100644
--- a/lib/utils/web-entry.js
+++ b/lib/utils/web-entry.js
@@ -33,7 +33,7 @@ function onUpdate () {
   }
 }
 
-function updateScroll (prevRouterProps, nextRouterProps) {
+function defaultShouldUpdateScroll (prevRouterProps, nextRouterProps) {
   if (shouldUpdateScroll) {
     return shouldUpdateScroll(prevRouterProps, nextRouterProps)
   }
@@ -66,7 +66,7 @@ loadConfig(() =>
       <Router
         history={browserHistory}
         routes={routes}
-        render={applyRouterMiddleware(useScroll(updateScroll))}
+        render={applyRouterMiddleware(useScroll(defaultShouldUpdateScroll))}
         onUpdate={onUpdate}
       />,
       typeof window !== 'undefined' ? document.getElementById('react-mount') : undefined)