callback in JavaScript

Callbacks:

Definition:

A callback is a function that is passed as an argument to another function and is executed after the completion of a specific task. Callbacks are commonly used in asynchronous operations, such as handling events, making API requests, or reading files.

function fetchData(callback) {
  setTimeout(() => {
    const data = 'Callback Example Data';
    callback(data);
  }, 1000);
}

function processData(data) {
  console.log('Processing data:', data);
}

fetchData(processData);

In this example, fetchData is a function that simulates an asynchronous operation. It takes a callback function (processData) as an argument and invokes it once the operation is complete.

Callback Hell (Callback Pyramids):
Callback hell refers to the situation where multiple nested callbacks create code that is hard to read and maintain. This occurs when dealing with deeply nested asynchronous operations.