//Currying:
It is a technique in functional programming, transformation of the 
function of multiple arguments into several functions of a single 
argument in sequence. It is also called nested function is ecmascript

//Without currying
function calculateVolume(length, breadth, height) {
        return length * breadth * height;
    }
//With Currying
function calculateVolume(length) {
        return function (breadth) {
            return function (height) {
                return length * breadth * height;
            }
        }
    }

// Currying :
//- Currying is an advanced technique of working with functions.
function sum(a) {
  return function (b) {
    return function (c) {
      return function (d) {
        console.log("sun is:::", a + b + c + d);
      };
    };
  };
}
sum(5)(7)(3)(20);