What is the difference between closures and promises in JavaScript?

What is the difference between closures and promises in JavaScript?

Closures are functions that remember their outer variables, while promises are objects that represent the eventual completion of an asynchronous operation.

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 inner = outerFunction();
inner(); // Logs: I am from outer function

And how about a promise?

Here's an example of a promise:

let myPromise = new Promise((resolve, reject) => {
    let success = true;
    if (success) {
        resolve('Operation was successful!');
    } else {
        reject('Operation failed.');
    }
});

myPromise.then(result => console.log(result)).catch(error => console.log(error));

When should I use closures over promises?

Use closures when you need to maintain state or encapsulate variables, and use promises for handling asynchronous operations.