What are function closures in JavaScript?

What are function closures in JavaScript?

Function 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?

Sure! Here's a simple example:

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

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

Why are closures useful?

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

Are there any drawbacks to using closures?

Yes, closures can lead to memory leaks if not handled properly, as they can keep references to outer variables longer than necessary.