Let's understand a key term idempotence in functional programming

idempotence.js

//here i will try to explain a key concept idempotence with example
function notIdempotenceFn(num) {
  return Math.random(num);
}

notIdempotenceFn(5);
notIdempotenceFn(5);
// the output of above two function will be differeht however passing the same input so the function is not idempotent

function idempotentFn(num) {
   console.log(num);
}

// The above function is idempotent because every time we call it, it does the same thing for same input so it is idempotent
// it is not pure because it is alter its outside world  as console.log will log in window 

//Another feature of idempotence is the ability to call itself again and again and still the output is the same let see this with 
// an example
function getAbsolute(x) {
  return Math.abs(x)
}
getAbsolute(getAbsolute(getAbsolute(-50))) //50

// I am calling getAbsolute function again and again but it output will be the same.