refactoring reducer

src/components/book-list/book-list.js

@@ -45,7 +45,7 @@ class BookListContainer extends Component {
   }
 };
 
-const mapStateToProps = ({ books, loading, error }) => {
+const mapStateToProps = ({bookList: { books, loading, error }}) => {
   return { books, loading, error }
 }
 

src/components/shopping-cart-table/shopping-cart-table.js

@@ -58,7 +58,7 @@ const ShoppingCartTable = ({ items, total, onIncrease, onDecrease, onDelete }) =
   )
 };
 
-const mapStateToProps = ({ cartItems, orderTotal }) => {
+const mapStateToProps = ({ shoppingCart: { cartItems, orderTotal } }) => {
   return {
     items: cartItems,
     total: orderTotal

src/reducers/book-list.js

@@ -0,0 +1,38 @@
+
+const updateBookList = (state, action) => {
+
+  if (state === undefined) {
+    return {
+      books: [],
+      loading: true,
+      error: null
+    };
+  }
+
+  switch (action.type) {
+    case 'FETCH_BOOKS_REQUEST':
+      return {
+        books: [],
+        loading: true,
+        error: null
+      };
+
+    case 'FETCH_BOOKS_SUCCESS':
+      return {
+        books: action.payload,
+        loading: false,
+        error: null
+      };
+
+    case 'FETCH_BOOKS_FAILURE':
+      return {
+        books: [],
+        loading: false,
+        error: action.payload
+      };
+    default:
+      return state.bookList;
+  }
+};
+
+export default updateBookList

src/reducers/index.js

@@ -1,94 +1,11 @@
 
-const initialState = {
-  books: [],
-  loading: true,
-  error: null,
-  cartItems: [],
-  orderTotal: 590
-};
-
-const updateCartItems = (cartItems, item, idx) => {
-  if (item.count === 0) {
-    return [
-      ...cartItems.slice(0, idx),
-      ...cartItems.slice(idx + 1)
-    ]
-  };
-  if (idx === -1) {
-    return [
-      ...cartItems,
-      item
-    ]
-  };
-  return [
-    ...cartItems.slice(0, idx),
-    item,
-    ...cartItems.slice(idx + 1)
-  ];
-};
-
-const updateCartItem = (book, item = {}, quantity) => {
-  const { id = book.id, count = 0, title = book.title, total = 0 } = item;
-  return {
-    id,
-    title,
-    count: count + quantity,
-    total: total + quantity * book.price
-  }
-};
-
-const updateOrder = (state, bookId, quantity) => {
-  const { books, cartItems } = state;
-  const book = books.find(({ id }) => id === bookId);
-  const itemIndex = cartItems.findIndex(({ id }) => id === bookId);
-  const item = cartItems[itemIndex];
+import updateBookList from './book-list';
+import updateShoppingCart from './shopping-cart';
 
-  const newItem = updateCartItem(book, item, quantity);
+const reducer = (state, action) => {
   return {
-    ...state,
-    cartItems: updateCartItems(cartItems, newItem, itemIndex)
-  };
-};
-
-const reducer = (state = initialState, action) => {
-  //console.log(action.type);
-  switch (action.type) {
-    case 'FETCH_BOOKS_REQUEST':
-      return {
-        ...state,
-        books: [],
-        loading: true,
-        error: null
-      };
-
-    case 'FETCH_BOOKS_SUCCESS':
-      return {
-        ...state,
-        books: action.payload,
-        loading: false,
-        error: null
-      };
-
-    case 'FETCH_BOOKS_FAILURE':
-      return {
-        ...state,
-        books: [],
-        loading: false,
-        error: action.payload
-      };
-
-    case 'BOOK_ADDED_TO_CART':
-      return updateOrder(state, action.payload, 1);
-
-    case 'BOOK_REMOVE_FROM_CART':
-      return updateOrder(state, action.payload, -1);
-
-    case 'ALL_BOOKS_REMOVE_FROM_CART':
-      const item = state.cartItems.find(({ id }) => id === action.payload);
-      return updateOrder(state, action.payload, -item.count);
-
-    default:
-      return state;
+    bookList: updateBookList(state, action),
+    shoppingCart: updateShoppingCart(state, action)
   }
 };
 

src/reducers/shopping-cart.js

@@ -0,0 +1,70 @@
+
+const updateCartItems = (cartItems, item, idx) => {
+  if (item.count === 0) {
+    return [
+      ...cartItems.slice(0, idx),
+      ...cartItems.slice(idx + 1)
+    ]
+  };
+  if (idx === -1) {
+    return [
+      ...cartItems,
+      item
+    ]
+  };
+  return [
+    ...cartItems.slice(0, idx),
+    item,
+    ...cartItems.slice(idx + 1)
+  ];
+};
+
+const updateCartItem = (book, item = {}, quantity) => {
+  const { id = book.id, count = 0, title = book.title, total = 0 } = item;
+  return {
+    id,
+    title,
+    count: count + quantity,
+    total: total + quantity * book.price
+  }
+};
+
+const updateOrder = (state, bookId, quantity) => {
+  const { bookList: { books }, shoppingCart: { cartItems } } = state;
+  const book = books.find(({ id }) => id === bookId);
+  const itemIndex = cartItems.findIndex(({ id }) => id === bookId);
+  const item = cartItems[itemIndex];
+
+  const newItem = updateCartItem(book, item, quantity);
+  return {
+    orderTotal: 0,
+    cartItems: updateCartItems(cartItems, newItem, itemIndex)
+  };
+};
+
+const updateShoppingCart = (state, action) => {
+
+  if (state === undefined) {
+    return {
+      cartItems: [],
+      orderTotal: 0
+    }
+  }
+
+  switch (action.type) {
+    case 'BOOK_ADDED_TO_CART':
+      return updateOrder(state, action.payload, 1);
+
+    case 'BOOK_REMOVE_FROM_CART':
+      return updateOrder(state, action.payload, -1);
+
+    case 'ALL_BOOKS_REMOVE_FROM_CART':
+      const item = state.shoppingCart.cartItems.find(({ id }) => id === action.payload);
+      return updateOrder(state, action.payload, -item.count);
+
+    default:
+      return state.shoppingCart;
+  }
+};
+
+export default updateShoppingCart;