What are closures in JavaScript and can you give me examples?

What are closures in JavaScript and can you give me examples?

Closures are functions that have access to their outer function's scope even after the outer function has returned. For example, if you have a function that returns another function, the inner function can still access variables from the outer function.

Can you show me a code example of a closure?

Sure! Here's a simple example:

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

const innerFunc = outerFunction();
innerFunc(); // This will log: 'I am from outer function!'

What are some practical uses of closures?

Closures are often used for data encapsulation, creating private variables, and implementing function factories. They help maintain state in asynchronous programming as well.

Can closures lead to memory leaks?

Yes, if closures are not managed properly, they can lead to memory leaks by keeping references to variables that are no longer needed.