Add reselect

Author: adaam2

frontend/package.json

@@ -45,6 +45,7 @@
     "react-redux": "^5.0.7",
     "redux": "^3.7.2",
     "redux-thunk": "^2.2.0",
+    "reselect": "^3.0.1",
     "style-loader": "0.19.0",
     "superagent": "^3.8.2",
     "sw-precache-webpack-plugin": "0.11.4",

frontend/src/containers/app.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import { connect }  from 'react-redux';
 import { loadApp, checkApiStatus } from '../actions/app';
+import * as AppSelectors from '../selectors/app';
 
 // eslint-disable-next-line
 import styles from './app.css';
@@ -54,7 +55,7 @@ class App extends React.Component {
 
 export default connect((store, props) => {
   return {
-    loaded: store.app.loaded,
-    apiStatus: store.app.apiStatus
+    loaded: AppSelectors.getLoadedStatus(store),
+    apiStatus: AppSelectors.getApiStatus(store)
   };
 })(App);

frontend/src/reducers/app.js

@@ -2,7 +2,7 @@ import { ACTION_TYPES } from '../constants/action-types';
 
 const initialState = {
   loaded: false,
-  apiStatus: undefined
+  apiStatus: null
 };
 
 export default function app(state = initialState, action) {

frontend/src/selectors/app.js

@@ -0,0 +1,18 @@
+import { createSelector } from 'reselect';
+import _ from 'lodash';
+
+export const getAppStore = store => store.app;
+
+export const getApiStatus = createSelector(
+  [getAppStore],
+  (appStore) => {
+    return _.get(appStore, 'apiStatus');
+  }
+);
+
+export const getLoadedStatus = createSelector(
+  [getAppStore],
+  (appStore) => {
+    return _.get(appStore, 'loaded');
+  }
+);

frontend/yarn.lock

@@ -6070,6 +6070,10 @@ requires-port@1.0.x, requires-port@1.x.x, requires-port@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/requires-port/-/requires-port-1.0.0.tgz#925d2601d39ac485e091cf0da5c6e694dc3dcaff"
 
+reselect@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/reselect/-/reselect-3.0.1.tgz#efdaa98ea7451324d092b2b2163a6a1d7a9a2147"
+
 resolve-cwd@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/resolve-cwd/-/resolve-cwd-2.0.0.tgz#00a9f7387556e27038eae232caa372a6a59b665a"