Function overloading

Javascript doesn’t support Function overloading
If we try to define multiple functions with the same name and different arguments, then the last one will be executed:

function calculateArea(a, b) {
  return a * b;
}
 
function calculateArea(a) {
  return a * a;
}
 
console.log(calculateArea(5, 7));
// 25 incorrect
// executes the last function
 
console.log(calculateArea(5));
// 25 correct

But we can still achieve function overloading via dynamic arguments
- We need to assume the highest number of arguments
- Then we check if the argument is passed or not inside the function

function CatStrings(p1, p2, p3)
{
  var s = p1;
  if(typeof p2 !== "undefined") {s += p2;}
  if(typeof p3 !== "undefined") {s += p3;}
  return s;
};
 
CatStrings("one");        // result = one
CatStrings("one",2);      // result = one2
CatStrings("one",2,true); // result = one2true

Function overriding

When you inherit another class, we can override the parent method
In JS if you define multiple functions with the same name in the block then the last function will be called