What are JavaScript closures and how do they work?

What are JavaScript closures and how do they work?

JavaScript closures are functions that have access to their outer function's scope even after the outer function has returned.

Can you give me an example of a closure in JavaScript?

Sure! Here's a simple example:

function outerFunction() {
    let outerVariable = 'I am from outer scope!';
    function innerFunction() {
        console.log(outerVariable);
    }
    return innerFunction;
}

const closureFunction = outerFunction();
closureFunction(); // Outputs: I am from outer scope!

Why are closures useful in JavaScript?

Closures are useful for data encapsulation, creating private variables, and maintaining state in asynchronous programming.

Are there any common pitfalls when using closures?

Yes, one common pitfall is unintentionally creating memory leaks by keeping references to outer scope variables longer than needed.