Issue #2 - Handling Ecommerce Data with Arrays & Objects

JS Bytes Issue #2 - Become a better JS engineer

Welcome to the second issue of JS Bytes! You can read the first issue here.

Today, we’re focusing on a key skill for every JavaScript developer: working with data.

Arrays and objects are the foundation of data in JavaScript. Mastering them is crucial to handling information in your code.

Whether you're just starting or sharpening your skills, this issue will help you confidently understand and use these essential concepts.

JavaScript Problem Solving Challenge

You are given an array of objects (products) representing items from a dummy e-commerce store.

Each product object contains the following fields:

1. id

2. name

3. category

4. price

5. stock

6. sales

Your task is to solve the following 3 problems using this product database.

Ecommerce Products Database

const products = [
  {
    id: 1,
    name: 'Wireless Mouse',
    category: 'Electronics',
    price: 28.95,
    stock: 34,
    sales: 150,
  },
  {
    id: 2,
    name: 'Bluetooth Headphones',
    category: 'Electronics',
    price: 95.5,
    stock: 12,
    sales: 200,
  },
  {
    id: 3,
    name: 'Laptop',
    category: 'Electronics',
    price: 910.75,
    stock: 7,
    sales: 50,
  },
  {
    id: 4,
    name: 'Coffee Maker',
    category: 'Home Appliances',
    price: 45.3,
    stock: 0,
    sales: 85,
  },
  {
    id: 5,
    name: 'Smartphone',
    category: 'Electronics',
    price: 680.4,
    stock: 25,
    sales: 300,
  },
  {
    id: 6,
    name: 'Blender',
    category: 'Home Appliances',
    price: 37.6,
    stock: 10,
    sales: 45,
  },
  {
    id: 7,
    name: 'Desk Lamp',
    category: 'Home Decor',
    price: 18.8,
    stock: 50,
    sales: 70,
  },
  {
    id: 8,
    name: 'Office Chair',
    category: 'Furniture',
    price: 85.2,
    stock: 5,
    sales: 60,
  },
  {
    id: 9,
    name: 'Electric Kettle',
    category: 'Home Appliances',
    price: 23.7,
    stock: 0,
    sales: 90,
  },
  {
    id: 10,
    name: 'Running Shoes',
    category: 'Footwear',
    price: 57.45,
    stock: 20,
    sales: 120,
  },
  {
    id: 11,
    name: 'Air Conditioner',
    category: 'Home Appliances',
    price: 389.95,
    stock: 8,
    sales: 30,
  },
  {
    id: 12,
    name: 'Bookshelf',
    category: 'Furniture',
    price: 142.3,
    stock: 15,
    sales: 40,
  },
  {
    id: 13,
    name: 'Smartwatch',
    category: 'Electronics',
    price: 192.99,
    stock: 18,
    sales: 75,
  },
  {
    id: 14,
    name: 'Electric Toothbrush',
    category: 'Personal Care',
    price: 27.55,
    stock: 22,
    sales: 55,
  },
  {
    id: 15,
    name: 'Yoga Mat',
    category: 'Sports',
    price: 17.2,
    stock: 30,
    sales: 100,
  },
  {
    id: 16,
    name: 'Gaming Console',
    category: 'Electronics',
    price: 489.0,
    stock: 10,
    sales: 95,
  },
  {
    id: 17,
    name: 'Water Bottle',
    category: 'Sports',
    price: 9.5,
    stock: 40,
    sales: 85,
  },
  {
    id: 18,
    name: 'Microwave Oven',
    category: 'Home Appliances',
    price: 94.75,
    stock: 8,
    sales: 60,
  },
  {
    id: 19,
    name: 'T-Shirt',
    category: 'Apparel',
    price: 13.99,
    stock: 60,
    sales: 110,
  },
  {
    id: 20,
    name: 'Jeans',
    category: 'Apparel',
    price: 47.3,
    stock: 20,
    sales: 75,
  },
]

1. Group Products by Category

Problem:

Write a function called groupProductsByCategory that takes the products array as a parameter and returns an object where the keys are category names, and the values are arrays containing the products that belong to that category.

Clarification:

• Each product should be grouped under its respective category.

• Return an object where each category name is a key, and the value is an array of product objects.

function groupProductsByCategory(products) {
  // Your code here
}

Sample Output:

{
  "Electronics": [
    { id: 1, name: "Wireless Mouse", ... },
    { id: 2, name: "Bluetooth Headphones", ... },
    ...
  ],
  "Home Appliances": [
    { id: 4, name: "Coffee Maker", ... },
    ...
  ],
  "Furniture": [
    { id: 8, name: "Office Chair", ... },
    ...
  ]
}

2. Get Top N Selling Products

Problem:

Write a function called topSellingProducts that accepts two parameters: the products array and a number n representing the number of top-selling products you want to return. The function should return an array of the top N products sorted by their sales in descending order.

Clarification:

• Sort the products by their sales property.

• Return the top n products with the highest sales.

function topSellingProducts(products, n) {
  // Your code here
}

Sample Output (for n = 3):

[
  { id: 5, name: "Smartphone", sales: 300, ... },
  { id: 2, name: "Bluetooth Headphones", sales: 200, ... },
  { id: 1, name: "Wireless Mouse", sales: 150, ... }
]

3. Get Products with High Sales but Low Stock

Problem:

Write a function called getHighSalesLowStockProducts that takes three parameters: products, salesThreshold, and stockThreshold. The function should return an array of products that have sales greater than or equal to salesThreshold and stock less than or equal to stockThreshold.

Clarification:

• Only include products where the sales exceed or meet the salesThreshold and the stock is below or equal to the stockThreshold.

• Return the filtered array of products.

function getHighSalesLowStockProducts(
  products,
  salesThreshold,
  stockThreshold,
) {
  // Your code here
}

Sample Output (for salesThreshold = 100, stockThreshold = 10):

[
  { id: 16, name: "Gaming Console", sales: 95, stock: 10, ... },
  { id: 9, name: "Electric Kettle", sales: 90, stock: 0, ... }
]

---

3 Conceptual MCQs

1. What will be the output of the following code snippet?

const welcome = {
  name: 'Ali',
  greet: function () {
    const that = this
    return () => {
      console.log(`Hello, ${that.name}`)
    }
  },
}

const greetFunction = welcome.greet()
greetFunction()

A) Hello, undefined

B) Hello, Ali

C) TypeError: greetFunction is not a function

D) ReferenceError: that is not defined

2. What will be the output of the following code?

const arr = [1, , 3, , 5]

arr[10] = 10

console.log(arr.length)

A) 4

B) 6

C) 10

D) 11

3. What's the output?

let num = 0

for (let i = 1; i <= 5; i++) {
  if (i % 2 === 0) continue
  num += i
}

console.log(num)

A) 6

B) 9

C) 12

D) 15

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