What are the differences between Promises and Callbacks in Node.js?

What are the differences between Promises and Callbacks in Node.js?

In Node.js, callbacks are functions passed as arguments to other functions, executed after a task completes. Promises, on the other hand, are objects that represent the eventual completion (or failure) of an asynchronous operation, allowing for cleaner and more manageable code.

Can you give me an example of a callback in Node.js?

Sure! Here's a simple example:

const fs = require('fs');

fs.readFile('file.txt', 'utf8', (err, data) => {
    if (err) {
        console.error(err);
        return;
    }
    console.log(data);
});

In this example, readFile takes a callback that handles the result once the file is read.

How would that look using Promises?

Using Promises, the same operation would look like this:

const fs = require('fs').promises;

fs.readFile('file.txt', 'utf8')
    .then(data => console.log(data))
    .catch(err => console.error(err));

This approach is cleaner and allows for better error handling.

Which one is better to use?

Promises are generally preferred over callbacks because they help avoid callback hell, making the code easier to read and maintain. Additionally, Promises can be chained, allowing for more complex asynchronous operations to be handled more elegantly.