What is lexical scoping in JavaScript?

What is lexical scoping in JavaScript?

Lexical scoping refers to the way variable scope is determined in JavaScript. It means that a variable's scope is defined by its location within the source code, and nested functions have access to variables declared in their outer scope.

Can you give me an example of lexical scoping?

Sure! Here's a simple example:

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

In this case, innerFunction can access outerVariable because of lexical scoping.

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 current or outer scope, you'll get a ReferenceError. For example, if innerFunction tried to access a variable declared only in outerFunction, it would work, but if it tried to access a variable declared in a different function, it would fail.

How does this relate to closures?

Lexical scoping is fundamental to closures. A closure is created when a function retains access to its lexical scope, even when the function is executed outside that scope. This allows functions to remember the environment in which they were created.