Find first defined argument

defined.js

/**
 * Get first defined argument
 *
 * @param {...} any argument(s)
 * @return {Any} first defined argument
 */

exports.defined = function() {
  var args = Array.prototype.slice.call(arguments);
  for (var i = 0; i < args.length; i++) {
    var arg = args[i]
      , type = Object.prototype.toString.call(arg)
      ;
    // Check that arg is not undefined, null, or NaN
    if (type !== '[object Undefined]' && type !== '[object Null]' && !isNaN(arg)) {
      return arg;
    }
  }
  // Return last argument
  return args[args.length - 1];
};