Trying to explain curryfication

Curry.js

#!/usr/bin/env node

//Declare curry method on every functions
Function.prototype.curry = function(arg1) {
   //Keeping this just for later
   var self = this;

   //Keeping curried arg in the scope of the new function
   var arg1 = arg1;

   //Defining the new function which take one less parameter
   return function(arg2) {

      //Calling the original function with every parameters
      self.call(self, arg1, arg2);
   }
}

//One origin function taking to parameters and display them
var testFunction = function(un, deux) {
   console.log(un + ' ' + deux);
}

//Indian spice
var testFunctionUn = testFunction.curry('un');

//That should display 'un - deux'
testFunctionUn('deux');