Rework code splitting page per review feedback and add page

Author: markerikson

docs/recipes/CodeSplitting.md

@@ -1,13 +1,37 @@
+---
+id: code-splitting
+title: Code Splitting
+sidebar_label: Code Splitting
+hide_title: true
+---
+
 # Code Splitting
 In large web applications, it is often desirable to split up the app code into multiple JS bundles that can be loaded on-demand. This strategy, called 'code splitting', helps to increase performance of your application by reducing the size of the initial JS payload that must be fetched.
 
-To code split with Redux, we want to be able to dynamically add reducers to the store. The default usage of Redux mandates that a single root reducer should to be passed to the `configureStore` call, which makes dynamically adding new reducers more difficult. Below, we discuss some approaches to solving this problem and reference two libraries that provide this functionality.
+To code split with Redux, we want to be able to dynamically add reducers to the store. However, Redux really only has a single root reducer function.  This root reducer is normally generated by calling `combineReducers()` or a similar function when the application is initialized.  In order to dynamically add more reducers, we need to call that function again to re-generate the root reducer.  Below, we discuss some approaches to solving this problem and reference two libraries that provide this functionality.
 
 ## Basic Principle
-To dynamically add Reducers to a Redux store, there are two approaches that can be taken
 
 ### Using `replaceReducer`
-The Redux store exposes the `replaceReducer` function, which replaces the current active reducer function with a new reducer function. We can leverage this function to add a reducer as follows:
+
+The Redux store exposes a `replaceReducer` function, which replaces the current active root reducer function with a new root reducer function.  Calling it will swap the internal reducer function reference, and dispatch an action to help any newly-added slice reducers initialize themselves:
+
+```js
+const newRootReducer = combineReducers({
+    existingSlice : existingSliceReducer,
+    newSlice : newSliceReducer,
+})
+
+store.replaceReducer(newRootReducer)
+```
+
+## Reducer Injection Approaches
+
+### Defining an `injectReducer` function
+
+We will likely want to call `store.replaceReducer()` from anywhere in the application.  Because of that, it's helpful
+to define a reusable `injectReducer()` function that keeps references to all of the existing slice reducers, and attach
+that to the store instance. 
 
 ```javascript
 import { createStore } from 'redux';
@@ -131,8 +155,11 @@ To add a new reducer, one can now call `store.reducerManager.add("asyncState", a
 To remove a reducer, one can now call `store.reducerManager.remove("asyncState")`
 
 ## Libraries and Frameworks
+
 There are a few good libraries out there that can help you add the above functionality automatically:
- * [`redux-dynamic-reducer`](https://github.com/ioof-holdings/redux-dynamic-reducer)
-    * This library exposes the `addReducer` function on the Redux store to accomplish the behavior we described above. It also has React bindings which make it easier to add reducers within the React component lifecycle.
-* [`redux-dynamic-modules`](https://github.com/Microsoft/redux-dynamic-modules)
-    * This library introduces the concept of a 'Redux Module', which is a bundle of Redux artifacts (reducers, middleware) that should be dynamically loaded. It also exposes a React higher-order component to load 'modules' when areas of the application come online. Additionally, it has integrations with libraries like `redux-thunk` and `redux-saga` which also help dynamically load their artifacts (thunks, sagas). 
+
+ * [`redux-dynostore`](https://github.com/ioof-holdings/redux-dynostore): 
+    Provides tools for building dynamic Redux stores, including dynamically adding reducers and sagas, and React bindings to help you add in association with components. 
+* [`redux-dynamic-modules`](https://github.com/Microsoft/redux-dynamic-modules): 
+    This library introduces the concept of a 'Redux Module', which is a bundle of Redux artifacts (reducers, middleware) that should be dynamically loaded. It also exposes a React higher-order component to load 'modules' when areas of the application come online. Additionally, it has integrations with libraries like `redux-thunk` and `redux-saga` which also help dynamically load their artifacts (thunks, sagas).
+* [Redux Ecosystem Links: Reducers - Dynamic Reducer Injection](https://github.com/markerikson/redux-ecosystem-links/blob/master/reducers.md#dynamic-reducer-injection) 

website/sidebars.json

@@ -41,6 +41,7 @@
       "recipes/implementing-undo-history",
       "recipes/isolating-redux-sub-apps",
       "recipes/using-immutablejs-with-redux",
+      "recipes/code-splitting",
       {
         "type": "subcategory",
         "label": "Structuring Reducers",