Clojuresque Fibs in JS.

fibs.js

function allfibs(end) {
    var x = 0, y = 1, count = 1;
    yield 1;
    while (count++ < end) {
        [x,y] = [y,x + y];
        yield y;
    }
        
}

function fibs(x) {
  return [ i for (i in allfibs(x)) ]
}

fibs(5) // [1,1,2,3,5]