Array actions for Redux State Return

Avoiding array mutations with slice, concat and ...spread

const addCounter = (list) => {
  return [...list, 0];
};

const removeCounter = (list, index) => {
  return [
    ...list.slice(0, index),
    ...list.slice(index + 1)
  ];
};

const incrementCounter = (list, index) => {
  return [
    ...list.slice(0, index),
    list[index] + 1,
    ...list.slice(index + 1)
  ];
};