What is the difference between callback and promises in Node.js?

In Node.js, callbacks and promises are both used to handle asynchronous operations, but they differ in their execution and syntax.

A callback is a function that is passed as an argument to another function and is executed once the asynchronous operation is completed. Callbacks can lead to callback hell or pyramid of doom, making the code difficult to read and maintain.

On the other hand, a promise is an object that represents the eventual completion or failure of an asynchronous operation. Promises provide a more structured way to handle asynchronous code and allow chaining of multiple asynchronous operations.

With promises, you can use methods such as .then() and .catch() to handle the success and error cases respectively, making the code more readable and structured.

In summary, while callbacks are simpler and widely used in Node.js, promises offer a more organized and efficient way to handle asynchronous operations, reducing callback hell and improving code readability.