JavaScript - Currying

Create a new function that pre-fill in an argument to another function.
Use it like this:

      // a function that generates a new function for adding numbers
      function addGenerator(num) {
        return function(toAdd) {
          return num + toAdd;
        }
      }
     
      // using above, make this function
      var addFive = addGenerator(5);
      alert(addFive(4) == 9);

.