initial state

src/redux/reducers/authorReducer.js

@@ -1,6 +1,7 @@
 import * as types from "../actions/actionTypes";
+import initialState from "./initialState";
 
-export default function authorReducer(state = [], action) {
+export default function authorReducer(state = initialState.authors, action) {
   switch (action.type) {
     case types.LOAD_AUTHORS_SUCCESS:
       return action.authors;

src/redux/reducers/courseReducer.js

@@ -1,6 +1,7 @@
 import * as types from "../actions/actionTypes";
+import initialState from "./initialState";
 
-export default function courseReducer(state = [], action) {
+export default function courseReducer(state = initialState.courses, action) {
   switch (action.type) {
     case types.CREATE_COURSE:
       return [...state, { ...action.course }];

src/redux/reducers/initialState.js

@@ -0,0 +1,4 @@
+export default {
+  courses: [],
+  authors: []
+};