How do I use callbacks in promises?

How do I use callbacks in promises?

In JavaScript, promises are used to handle asynchronous operations. Callbacks can be used within promises to execute code after the promise is resolved.

Can you give me an example of using a callback with a promise?

Sure! Here's a simple example:

function fetchData() {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve('Data received!');
        }, 2000);
    });
}

fetchData().then(data => {
    console.log(data); // This is the callback that runs after the promise is resolved.
});

What happens if the promise is rejected?

If the promise is rejected, you can handle the error using the .catch() method. For example:

fetchData().then(data => {
    console.log(data);
}).catch(error => {
    console.error('Error:', error);
});