What are the differences between promises and callbacks in async code?

What are the differences between promises and callbacks in async code?

Promises and callbacks are both used to handle asynchronous operations, but they have key differences. Callbacks can lead to 'callback hell' where nested callbacks make code hard to read, while promises provide a cleaner, more manageable way to handle async operations with methods like .then() and .catch().

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

Sure! Here's a simple example:

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

myPromise.then(message => {
    console.log(message);
}).catch(error => {
    console.error(error);
});

What about callbacks? Can you show me how they work?

Absolutely! Here's an example of a callback:

function fetchData(callback) {
    let data = 'Data fetched!';
    callback(data);
}

fetchData((result) => {
    console.log(result);
});

Which one should I use in my projects?

It depends on your needs. For simpler tasks, callbacks might suffice, but for more complex async operations, promises (or even async/await) are generally recommended for better readability and error handling.