Callbacks in JS

Callbacks in JS are the functions that are passed as arguments to other functions. They are executed after the completion of the task. Callbacks are used to handle asynchronous operations in JavaScript.

function sqaure(n) {
  return n * n;
}
function cube(n) {
  return n * n * n;
}
 
function task(a, b, cb) {
  const value1 = fn(a);
  const value2 = fn(b);
  return value1 + value2;
}
 
task(2, 3, square); // 13
task(2, 3, cube); // 35

Need of Callbacks

Callbacks are used to handle asynchronous operations in JavaScript. For example, when you make an API call, you don't know when the response will come back. So, you pass a callback function to the API call, which will be executed after the response is received.