What is the scope chain in JavaScript?

What is the scope chain in JavaScript?

The scope chain in JavaScript is a mechanism that determines the accessibility of variables in nested functions. It allows inner functions to access variables from their own scope and from outer scopes.

Can you give me an example of how the scope chain works?

Sure! Consider this code:

function outerFunction() {
    let outerVar = 'I am outside!';
    function innerFunction() {
        console.log(outerVar);
    }
    innerFunction();
}
outerFunction();

Here, innerFunction can access outerVar because of the scope chain.

What happens if I try to access a variable from a different scope?

If you try to access a variable from a different scope that is not in the chain, you'll get a ReferenceError. For example, if innerFunction tried to access a variable defined only in another function, it wouldn't work.