What are closures in JavaScript and how do they affect performance?

What are closures in JavaScript and how do they affect performance?

Closures are functions that retain access to their lexical scope, even when the function is executed outside that scope. This can impact performance by increasing memory usage if not managed properly.

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

Sure! Here's a simple example:

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

const innerFunc = outerFunction();
innerFunc(); // Outputs: I am outside!

How do closures help in data encapsulation?

Closures allow you to create private variables that cannot be accessed from outside the function, thus encapsulating the data and preventing unwanted modifications.

Are there any performance drawbacks to using closures?

Yes, closures can lead to higher memory consumption because they keep references to their outer scope. If not used wisely, this can lead to memory leaks.