function* hanoi(n, source, target, spare) {
  if (n === 0) {
    return;
  }
  yield* hanoi(n - 1, source, spare, target);
  yield { disk: n, from: source, to: target };
  yield* hanoi(n - 1, spare, target, source);
}

// Nothing runs until a move is asked for, so the caller sets the pace.
const moves = hanoi(3, "A", "C", "B");
for (const { disk, from, to } of moves) {
  console.log(`Move disk ${disk} from ${from} to ${to}`);
}