Bonfire: Arguments Optional

bonfire-arguments-optional.js

// Bonfire: Arguments Optional
// Author: @clive-bunting
// Challenge: http://www.freecodecamp.com/challenges/bonfire-arguments-optional
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function add() {
  if (typeof arguments[0] !== "number") {
    return undefined;
  }
  
  var first = arguments[0];
  
  if (arguments[1] === undefined) {
    return function() {
      if (typeof arguments[0] !== "number") {
        return undefined;
      }
      return first + arguments[0];
    };
  }
  if (typeof arguments[1] !== "number") {
    return undefined;
  }
  return first + arguments[1];
}

add(2,3);