cycle.js

function* cycle(list) {
  const arr = [...list]
  let i = 0
  for (;;) {
    i = (i + ((yield arr[i]) || 1)) % arr.length
  }
}

const it = cycle(['a', 'b', 'c'])

console.log(...[it.next(), it.next(), it.next(), it.next(), it.next(2), it.next(-1), it.next(-1)].map(x => x.value)) // a b c a c b a