repeatPattern2.js

function cycle(xs){
  let els = xs
  let index = 0
  return {
    next: function() {
      if(index === els.length) // cycle
        index = 0
      return {value: els[index++], done: false}
    }
  }
}
function take(n,xs){
  let it =  xs
  let taken = []
  let nxt
  while(n > 0){
    if((nxt = it.next()).done)
      return taken
    taken.push(nxt.value)
    n--
  }
  return taken
}
function repeatPattern2(xs,n){
  let times = xs.length * n
  return  take(times,cycle(xs))
}