Technical Architect Brain: Currying In Javascript

Currying is a technique of evaluating the function with multiple arguments, into a sequence of function with a single argument.

In other words, when a function, instead of taking all arguments at one time, takes the first one and return a new function that takes the second one and returns a new function which takes the third one, and so forth until all arguments have been fulfilled.

consider below example code:

var add =   function (a){
        return function(b){
                       return function(c){
                              return a+b+c;
                          }        
                    }
 }
console.log(add(2)(3)(4)); //output 9
console.log(add(3)(4)(5)); //output 12

this currying achieving through closures, so above program variables a,b private properties of the parent function

Why Useful Currying?