Variadic js...

variadic.js

Function.prototype.variadic = function () {
  var self = this

  return function () {

    return self.apply(self,
      self.length == 1 ?

        [arguments] :

        Array.prototype.reduce.call(arguments, function (a,x,i) {

          return (i + 1 < self.length ?

            a[i] = x :

            (rest = a[self.length -1],
            typeof rest !== 'undefined' && rest != null) ?
              rest.push(x) :
              a[self.length -1] = [x]), a

        }, []))
  }
}

Function.prototype.spread = function (a) {
  return this.apply(null, a)
}

var snoop = function (args) {
  console.log.apply(console, args)
  return args[0]
}.variadic()

var car = function (car, cdr) { return car }.variadic()
var cdr = function (car, cdr) { return cdr }.variadic()
var sum = function (car, cdr) { return cdr ? car + sum.spread(cdr) : car }.variadic()

snoop(
  car(1,2,3,4,5),
  cdr(1,2,3,4,5),
  sum(1,2,3,4,5))