From 21f4f577774233e6ad3c78103fbdbad39ba69ff6 Mon Sep 17 00:00:00 2001
From: Ryan Florence <rpflorence@gmail.com>
Date: Wed, 6 Aug 2014 23:32:41 -0600
Subject: [PATCH] [added] preserveScrollPosition Route/Routes props

closes #121
---
 docs/api/components/Route.md  |  6 ++++++
 docs/api/components/Routes.md | 11 +++++++++--
 modules/components/Route.js   |  9 ++++++++-
 modules/components/Routes.js  | 16 +++++++++++++++-
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/docs/api/components/Route.md b/docs/api/components/Route.md
index f225ff12a0..acc1d35f91 100644
--- a/docs/api/components/Route.md
+++ b/docs/api/components/Route.md
@@ -23,6 +23,12 @@ inherit the path of their parent.
 
 The component to be rendered when the route is active.
 
+### `preserveScrollPosition`
+
+If `true`, the router will not scroll the window up when the route is
+transitioned to. Defaults to `false`. Ignored if the parent `<Routes/>`
+has been set to `true`.
+
 ### `children`
 
 Routes can be nested. When a child route matches, the parent route's
diff --git a/docs/api/components/Routes.md b/docs/api/components/Routes.md
index 70f95916ac..14e8b943da 100644
--- a/docs/api/components/Routes.md
+++ b/docs/api/components/Routes.md
@@ -17,8 +17,15 @@ works without a server, if you use `history` your server will need to
 support it.
 
 For browsers that don't support the HTML5 history API the router will
-fall back to `window.location` if you choose `history`. This way all
-users get the same urls and can share them.
+fall back to `window.location` if you choose `history`, in other words,
+the router will simply cause a full page reload. This way all users get
+the same urls and can share them.
+
+### `preserveScrollPosition`
+
+If `true`, the router will not scroll the window up globally when any
+route is transitioned to. Defaults to `false`. When `false`, the
+`<Route/>` gets to decide whether or not to scroll on transition.
 
 Example
 -------
diff --git a/modules/components/Route.js b/modules/components/Route.js
index b42bccc29c..7085f1a82a 100644
--- a/modules/components/Route.js
+++ b/modules/components/Route.js
@@ -72,10 +72,17 @@ var Route = React.createClass({
 
   },
 
+  getDefaultProps: function() {
+    return {
+      preserveScrollPosition: false
+    };
+  },
+
   propTypes: {
     handler: React.PropTypes.any.isRequired,
     path: React.PropTypes.string,
-    name: React.PropTypes.string
+    name: React.PropTypes.string,
+    preserveScrollPosition: React.PropTypes.bool
   },
 
   render: function () {
diff --git a/modules/components/Routes.js b/modules/components/Routes.js
index 55edf01727..3b51346828 100644
--- a/modules/components/Routes.js
+++ b/modules/components/Routes.js
@@ -54,11 +54,13 @@ var Routes = React.createClass({
 
   propTypes: {
     location: React.PropTypes.oneOf([ 'hash', 'history' ]).isRequired,
+    preserveScrollPosition: React.PropTypes.bool
   },
 
   getDefaultProps: function () {
     return {
-      location: 'hash'
+      location: 'hash',
+      preserveScrollPosition: false
     };
   },
 
@@ -339,6 +341,8 @@ function syncWithTransition(routes, transition) {
         })
       };
 
+      // TODO: add functional test
+      maybeScrollWindow(routes, toMatches[toMatches.length - 1]);
       routes.setState(state);
 
       return state;
@@ -436,4 +440,14 @@ function reversedArray(array) {
   return array.slice(0).reverse();
 }
 
+function maybeScrollWindow(routes, match) {
+  if (routes.props.preserveScrollPosition)
+    return;
+
+  if (!match || match.route.props.preserveScrollPosition)
+    return;
+
+  window.scrollTo(0, 0);
+}
+
 module.exports = Routes;