Summary  
This chapter covers how to declare and use mutable (`let`) and immutable (`const`) variables and outlines naming best practices for clear, descriptive identifiers.

General domain of usage  
Game development (e.g., tracking player scores and maximum players)

Variables let you store data that can change, while constants store values that should stay the same.
Use:
- `let`: when the value can change;
- `const`: when the value should not change.

let score = 10;
score = 15; // value can change
console.log(score);

const maxPlayers = 4;
// maxPlayers = 5; // ❌ error

### Best Practices
- Use `const` by default;
- Use `let` only when needed;


## Naming Variables
Use clear and descriptive names:
```js
let playerScore = 100;
let maxLevel = 10;
```
Avoid:
- Starting with numbers;
- Reserved words;
- Unclear names like `x` or `data`.


### Why This Matters
Variables are the foundation of everything in JavaScript.
You'll use them to store user data, application state, and results.

Learn how to write JavaScript to control behavior in web applications. Work with variables, conditions, functions, arrays, and objects to build and organize logic. Handle user interactions, update content in the browser, and work with asynchronous code using promises and APIs. Prepare for building dynamic interfaces with Vue.js by understanding how data and logic drive UI.

Variables and Constants

Best Practices

Naming Variables

Why This Matters