cons, car, and cdr using only functions in JS

cons.js

function cons (a, b) {
  return function (sel) {
    return sel(a, b)
  }
}

function car (l) {
  return l(function (a, b) {
    return a
  })
}

function cdr (l) {
  return l(function (a, b) {
    return b
  })
}

var l = cons(1, cons(2, cons(3, null)));
console.log(
  car(l) // 1
, car(cdr(l)) // 2
, car(cdr(cdr(l))) //3
, cdr(cdr(cdr(l))) //null
);