index.js

/**
 * @typedef Item
 * @property {number} id - this item's ID
 * @property {string} name - name of this item
 * @property {number} price - price of this item
 * @property {string} category - the food group this item belongs to
 * @property {number} quantity - number of this item in inventory
 */

// ------------------ Complete the functions written below ------------------------------ //

/**
 * Prints out the name of each item in the given array.
 * @param {Item[]} items - array of items
 */
function logNames(items) {
  items.forEach(item => console.log(item.name));
 }

/**
 * @param {Item[]} items - array of items
 * @returns {string[]} an array of item names in all uppercase
 */
function getUppercaseNames(items) {
  return items.forEach((item) => console.log(item.name.toUpperCase()))

}

/**
 * @param {Item[]} items - array of items
 * @param {number} id - id of the item to find
 * @returns {Item} - the item in `items` with the given `id`
 */
function getItemById(items, id) {
  return items.find(item => item.id === id);
}

/**
 * @param {Item[]} items - array of items
 * @param {string} name - name of the item to find
 * @returns {number} the price of the item named `name`
 */
function getItemPriceByName(items, name) {
  const price = items.find(item => name === item.name)
  return price ? price.price : undefined
  // 1. find item by its name
  // 2. use item name to get its price
  // 3. return item price

}

/**
 * @param {Item[]} items - array of items
 * @param {string} category
 * @returns {Item[]} array of items that belong to the given `category`
 */
function getItemsByCategory(items, category) {
  return items.filter(item => category === item.category )
  // 1. use filter to find the items
  // 2. return items

}

/**
 * @returns {number} the total quantity of all items
 */
function countItems(items) {
  return items.reduce((sum, num) => sum + num.quantity, 0);

  // 1. use reduce to add the sum of the quantites
  // 2. return sum
  }

/**
 * @param {Item[]} items - array of items
 * @returns {number} the cost of all given items
 */
function calculateTotalPrice(items) {
  return items.reduce((sum, num) => sum + num.price, 0)
}

// --------------------- DO NOT CHANGE THE CODE BELOW ------------------------ //

/** @type {Item[]} */
const INVENTORY = [
  { id: 1, name: "apple", price: 1.75, category: "fruit", quantity: 100 },
  { id: 2, name: "banana", price: 0.25, category: "fruit", quantity: 137 },
  { id: 3, name: "orange", price: 1.0, category: "fruit", quantity: 10 },
  { id: 4, name: "broccoli", price: 3.0, category: "vegetable", quantity: 67 },
  { id: 6, name: "milk", price: 5.75, category: "dairy", quantity: 90 },
  { id: 7, name: "cheddar", price: 4.0, category: "dairy", quantity: 63 },
  { id: 8, name: "sourdough", price: 5.5, category: "grains", quantity: 81 },
];

console.log("Welcome! We carry the following items:");
logNames(INVENTORY);

console.log("Here are the names again in all uppercase:");
console.log(getUppercaseNames(INVENTORY));

console.log(`In total, we have ${countItems(INVENTORY)} items in stock.`);

const totalCost = calculateTotalPrice(INVENTORY);
console.log(
  `It would cost $${totalCost?.toFixed(2)} to purchase everything in stock.`
);

const itemId = prompt("Enter the ID of an item:", "1");
console.log(`The item with id #${itemId} is:`);
console.log(getItemById(INVENTORY, +itemId));

const itemName = prompt("Enter the name of an item:", "apple");
console.log(
  `The price of ${itemName} is ${getItemPriceByName(INVENTORY, itemName)}.`
);

const category = prompt("Enter a category you would like to see:", "fruit");
console.log(`The items in the ${category} category are:`);
console.log(getItemsByCategory(INVENTORY, category));