How do I use block scoping in JavaScript?

How do I use block scoping in JavaScript?

Block scoping in JavaScript is achieved using let and const. Unlike var, these keywords limit the variable's scope to the block in which they are defined.

Can you give me an example of block scoping?

Sure! Here's an example:

if (true) {
    let x = 10;
    const y = 20;
    console.log(x, y); // 10, 20
}
console.log(x); // ReferenceError: x is not defined

What happens if I use var instead?

If you use var, the variable is function-scoped or globally scoped, meaning it can be accessed outside the block:

if (true) {
    var z = 30;
}
console.log(z); // 30

Are there any best practices for using block scoping?

Yes! Use let and const instead of var to avoid hoisting issues and to keep your code cleaner and more predictable.