Let and Const

👨‍💼 We're building a shopping cart system. Some values will change as users interact (like the cart total), while others stay constant (like tax rates and product prices).

🐨 Open

index.ts

and:

Create a const for TAX_RATE set to 0.08
Create a let for cartTotal starting at 0
Create const variables for product prices: bookPrice, muffinPrice, and laptopPrice
Add items to the cart by updating cartTotal
Try to reassign TAX_RATE and see what TypeScript says

💰 By convention, constants that represent fixed values are often UPPER_CASE:

const MAX_ITEMS = 100
const API_URL = 'https://api.example.com'

📜 MDN - const

This is the first exercise where you'll be exporting values for the tests! For a reminder on how to do that, check out the previous page.

02. Variables and Immutability/01. Let and Const (💪 problem)

Let and Const