Can closures be used in asynchronous code?

Can closures be used in asynchronous code?

Yes, closures can be used in asynchronous code. They allow you to maintain access to variables from the outer function.

Can you give me an example of that?

Sure! Here's a simple example in JavaScript:

function outerFunction() {
    let outerVariable = 'I am from outer function';
    setTimeout(function() {
        console.log(outerVariable);
    }, 1000);
}

outerFunction();

What happens if the outer function is called multiple times?

Each call to outerFunction creates a new closure, so each timeout will log its own outerVariable value.

Are there any performance concerns with using closures in async code?

Generally, closures are efficient, but excessive use can lead to memory leaks if not managed properly.