What is the scope of a constant in JavaScript?

What is the scope of a constant in JavaScript?

In JavaScript, a constant declared with const has block scope, meaning it's only accessible within the block it's defined.

Can you give me an example of block scope with const?

Sure! Here's an example:

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

What happens if I try to reassign a const variable?

If you try to reassign a const variable, you'll get a TypeError. For example:

const y = 5;
y = 10; // TypeError: Assignment to constant variable.

Are there any exceptions to this rule?

Yes, while you can't reassign a const variable, if it's an object or array, you can still modify its properties or elements.