From 2c7e57152078bafc01edd888b169eee3f3b71722 Mon Sep 17 00:00:00 2001
From: Berkeley Martinez <berkeleytrue@users.noreply.github.com>
Date: Tue, 16 Jan 2018 09:49:36 -0800
Subject: [PATCH] feat(Panes): Do not update state if panes are the same

This reduces the number of updates required when transitioning between
challenges while preserving the state of the panes when going from two
similar challengees.
---
 common/app/Panes/redux/index.js | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/common/app/Panes/redux/index.js b/common/app/Panes/redux/index.js
index 511a159830..02a7f028c6 100644
--- a/common/app/Panes/redux/index.js
+++ b/common/app/Panes/redux/index.js
@@ -166,24 +166,22 @@ export default function createPanesAspects({ createPanesMap }) {
         const panesMap = action.meta.panesMap;
         const panes = _.map(panesMap, (name, type) => ({ name, type }));
         const numOfPanes = Object.keys(panes).length;
-        const panesByName = _.isEqual(state.panes, panes) && state.panesByName;
+        if (_.isEqual(state.panes, panes)) {
+          return state;
+        }
         return {
           ...state,
           panesMap,
           panes,
-          panesByName: panesByName
-            ? panesByName
-            : panes.reduce((panes, { name }, index) => {
-                const dividerLeft = utils.getDividerLeft(numOfPanes, index);
-                panes[name] = {
-                  name,
-                  dividerLeft,
-                  isHidden: false
-                };
-                return panes;
-              },
-            {}
-          )
+          panesByName: panes.reduce((panes, { name }, index) => {
+            const dividerLeft = utils.getDividerLeft(numOfPanes, index);
+            panes[name] = {
+              name,
+              dividerLeft,
+              isHidden: false
+            };
+            return panes;
+          }, {})
         };
       }
       if (action.meta && action.meta.isPaneAction) {