17.19 Refactoring Reducers

reducers/burgerBuilder.js

src\store\reducers\burgerBuilder.js

import * as actionTypes from "../actions/actionTypes";
import { updateObject } from "../utility";

const initialState = {
  ingredients: null,
  totalPrice: 4,
  error: false,
};

const INGREDIENT_PRICES = {
  salad: 0.5,
  cheese: 0.4,
  meat: 1.3,
  bacon: 0.7,
};

const reducer = (state = initialState, action) => {
  switch (action.type) {
    case actionTypes.ADD_INGREDIENT:
      const updatedIngredient = {
        [action.ingredientName]: state.ingredients[action.ingredientName] + 1,
      };
      const updatedIngredients = updateObject(
        state.ingredients,
        updatedIngredient
      );
      const updatedState = {
        ingredients: updatedIngredients,
        totalPrice: state.totalPrice + INGREDIENT_PRICES[action.ingredientName],
      };
      return updateObject(state, updatedState);
    case actionTypes.REMOVE_INGREDIENT:
      const updatedIng = {
        [action.ingredientName]: state.ingredients[action.ingredientName] - 1,
      };
      const updatedIngs = updateObject(state.ingredients, updatedIng);
      const updatedSt = {
        ingredients: updatedIngs,
        totalPrice: state.totalPrice + INGREDIENT_PRICES[action.ingredientName],
      };
      return updateObject(state, updatedSt);
    case actionTypes.SET_INGREDIENTS:
      return updateObject(state, {
        ingredients: {
          salad: action.ingredients.salad,
          bacon: action.ingredients.bacon,
          cheese: action.ingredients.cheese,
          meat: action.ingredients.meat,
        },
        totalPrice: 4,
        error: false,
      });
    case actionTypes.FETCH_INGREDIENTS_FAILED:
      return updateObject(state, { error: true });
    default:
      return state;
  }
};

export default reducer;

reducers/order.js

src\store\reducers\order.js

import * as actionTypes from "../actions/actionTypes";
import { updateObject } from "../utility";

const initialState = {
  orders: [],
  loading: false,
  purchased: false,
};

const reducer = (state = initialState, action) => {
  switch (action.type) {
    case actionTypes.PURCHASE_INIT:
      return updateObject(state, { purchased: false });
    case actionTypes.PURCHASE_BURGER_START:
      return updateObject(state, { loading: true });
    case actionTypes.PURCHASE_BURGER_SUCCESS:
      const newOrder = updateObject(action.orderData, { id: action.orderId });
      return updateObject(state, {
        loading: false,
        purchased: true,
        orders: state.orders.concat(newOrder),
      });
    case actionTypes.PURCHASE_BURGER_FAIL:
      return updateObject(state, { loading: false });
    case actionTypes.FETCH_ORDERS_START:
      return updateObject(state, { loading: true });
    case actionTypes.FETCH_ORDERS_SUCCESS:
      return updateObject(state, { orders: action.orders, loading: false });
    case actionTypes.FETCH_ORDERS_FAIL:
      return updateObject(state, { loading: false });
    default:
      return state;
  }
};

export default reducer;

New utility.js

src\store\utility.js

export const updateObject = (oldObject, updatedProperties) => {
  return {
    ...oldObject,
    ...updatedProperties,
  };
};