Cart Total Calculator
A cart contains items with a price and quantity. Build a summary that calculates subtotal, discount, tax, and final total.
Write these functions:
calculateSubtotal(items) should add price * quantity for every item.
calculateDiscount(subtotal, discountPercent) should return the discount amount.
calculateTax(amountAfterDiscount, taxPercent) should return the tax amount after the discount.
createCartSummary(items, discountPercent, taxPercent) should return an object with subtotal, discount, tax, and total.
Sample checks:
const cartItems = [ { name: 'Notebook', price: 10, quantity: 2 }, { name: 'Pen', price: 2, quantity: 5 }, { name: 'Bag', price: 30, quantity: 1 },];console.log(createCartSummary(cartItems, 10, 5));console.log(calculateSubtotal(cartItems));const singleItemCart = [{ name: 'Mouse', price: 25, quantity: 2 }];console.log(createCartSummary(singleItemCart, 0, 10));
Expected output:
{ subtotal: 60, discount: 6, tax: 2.7, total: 56.7 }60{ subtotal: 50, discount: 0, tax: 5, total: 55 }
The subtotal must include every item and multiply each item's price by its quantity.
Solution
Solution:
function calculateSubtotal(items) { let subtotal = 0; for (const item of items) { subtotal += item.price * item.quantity; } return subtotal;}function calculateDiscount(subtotal, discountPercent) { return (subtotal * discountPercent) / 100;}function calculateTax(amountAfterDiscount, taxPercent) { return (amountAfterDiscount * taxPercent) / 100;}function createCartSummary(items, discountPercent, taxPercent) { const subtotal = calculateSubtotal(items); const discount = calculateDiscount(subtotal, discountPercent); const amountAfterDiscount = subtotal - discount; const tax = calculateTax(amountAfterDiscount, taxPercent); const total = amountAfterDiscount + tax; return { subtotal, discount, tax, total, };}const cartItems = [ { name: 'Notebook', price: 10, quantity: 2 }, { name: 'Pen', price: 2, quantity: 5 }, { name: 'Bag', price: 30, quantity: 1 },];console.log(createCartSummary(cartItems, 10, 5));console.log(calculateSubtotal(cartItems));const singleItemCart = [{ name: 'Mouse', price: 25, quantity: 2 }];console.log(createCartSummary(singleItemCart, 0, 10));
