From 6c3dcc34343e24b91c8aa739ad198544cb7db90d Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Wed, 13 Dec 2017 13:06:05 +0100
Subject: [PATCH] Data Module: Update the dynamicReducer implementation and fix
 inline JS docs

---
 data/index.js           | 26 ++++++++++++++------------
 editor/store/persist.js |  3 ++-
 editor/store/reducer.js |  1 -
 editor/store/store.js   |  5 +++--
 4 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/data/index.js b/data/index.js
index d6ceded617eea7..2a48b3f9bbe15d 100644
--- a/data/index.js
+++ b/data/index.js
@@ -12,10 +12,9 @@ const enhancers = [];
 if ( window.__REDUX_DEVTOOLS_EXTENSION__ ) {
 	enhancers.push( window.__REDUX_DEVTOOLS_EXTENSION__() );
 }
-const store = createStore( dynamicReducer, {}, flowRight( enhancers ) );
 
 /**
- * Reducer function combining the dynamic "reducers" array
+ * Combines the dynamic "reducers" array to create one reducer
  *
  * @param {Object} state  Global state
  * @param {Object} action Action
@@ -23,19 +22,22 @@ const store = createStore( dynamicReducer, {}, flowRight( enhancers ) );
  * @return {Object}       Updated global state
  */
 function dynamicReducer( state = {}, action ) {
-	let hasChanges = false;
-	const newState = {};
-	reducers.forEach( ( { key, reducer } ) => {
-		const newSubState = reducer( state[ key ] || {}, action );
-		hasChanges = hasChanges || newSubState !== state[ key ];
-		newState[ key ] = newSubState;
-	} );
-
-	return hasChanges ? newState : state;
+	let hasChanged = false;
+	const nextState = {};
+	for ( let i = 0; i < reducers.length; i++ ) {
+		const { key, reducer } = reducers[ i ];
+		const previousStateForKey = state[ key ];
+		const nextStateForKey = reducer( previousStateForKey, action );
+		nextState[ key ] = nextStateForKey;
+		hasChanged = hasChanged || nextStateForKey !== previousStateForKey;
+	}
+	return hasChanged ? nextState : state;
 }
 
+const store = createStore( dynamicReducer, {}, flowRight( enhancers ) );
+
 /**
- * Register a new sub reducer to the global sate
+ * Registers a new sub reducer to the global state
  *
  * @param {String} key     Reducer key
  * @param {Object} reducer Reducer function
diff --git a/editor/store/persist.js b/editor/store/persist.js
index b614b2d559fd1e..0dac962c6e5fa1 100644
--- a/editor/store/persist.js
+++ b/editor/store/persist.js
@@ -35,7 +35,8 @@ export function withRehydratation( reducer, reducerKey ) {
 }
 
 /**
- * Load the initial state and persist on changes
+ * Loads the initial state and persist on changes
+ *
  * This should be executed after the reducer's registration
  *
  * @param {String}     reducerKey  The reducer key to persist (example: reducerKey.subReducerKey)
diff --git a/editor/store/reducer.js b/editor/store/reducer.js
index fb784cb98c2bbb..74025122900729 100644
--- a/editor/store/reducer.js
+++ b/editor/store/reducer.js
@@ -709,7 +709,6 @@ export function metaBoxes( state = defaultMetaBoxState, action ) {
 	}
 }
 
-// Create responsive reducer with the breakpoints imported from the scss variables file.
 export function browser( state = {}, action ) {
 	if ( action.type === 'BROWSER_RESIZE' ) {
 		return { width: action.width, height: action.height };
diff --git a/editor/store/store.js b/editor/store/store.js
index 377274bb6d099b..1d26d312d14a94 100644
--- a/editor/store/store.js
+++ b/editor/store/store.js
@@ -17,8 +17,9 @@ import { mobileMiddleware } from '../utils/mobile';
 import effects from './effects';
 
 /**
- * This function applies the custom middlewares used specifically in the editor moodule
- * It also restricts the getState call to the module's partial state only.
+ * Applies the custom middlewares used specifically in the editor module
+ *
+ * It also restricts the getState call to the module's partial state only
  *
  * @return {Object} Redux custom store
  */