053-Callback-Hell.js

/*
author : Jaydatt Patel

Callback hell is a phenomenon where a Callback is called inside another Callback. It is the nesting of multiple Callbacks inside a function. If you look at the design of the code, it seems just like a pyramid. Thus the Callback hell is also referred to as the ‘Pyramid of Doom’.

Callback hell structurally is just a nesting of function calls inside a function. But, it becomes difficult to understand and keep track of the nesting once the size of the nesting is increased.
*/

function print(i) {
  console.log("This is call number " + i);
}

function fun(callback) {
  setTimeout(() => {
    let i = 1;
    callback(i);
    i++;
    setTimeout(() => {
      callback(i);
      i++;
      setTimeout(() => {
        callback(i);
        i++;
        setTimeout(() => {
          callback(i);
          i++;
          setTimeout(() => {
            callback(i);
            i++;
            // .... and so on
          }, 800);
        }, 700);
      }, 500);
    }, 300);
  }, 100);
}

fun(print);