Showing off cool ES6/7 features

functionalFibs.js

/* This would be slow as hell in practice
 * because the algorithm is quadratic; the list
 * is recomputed every time. But oh, the
 * simplicity is refreshing.
 * 
 * Exercise for you, gist reader: implement
 * this same thing with Immutable.js.
 */
 
function fibs([...nums], max) {
  let next = [...nums].slice(-2).reduce((x, y) => x + y);
  if(next > max) {
  	return [...nums];
  }
  return fibs([...nums, next], max);
}

//Example:
(function() {
  let r = fibs([0, 1], 1000);
  console.log(r);
})();