push item to array if array has no this item

let a = [1, 2, 3, 4, 5];
let b = [10, 11, 12];

function pushItem(arr, item) {
  if (!arr.includes(item)) {
    arr.push(item);
  }
  return arr;
}

pushItem(a, 1)
pushItem(b, 11)

function pushItem2(arr, item) {
  if (!arr.includes(item)) {
    arr.push(item);
  }
  return arr;
}

pushItem2(a, 1)
pushItem2(b, 11)

function pushItem3(arr, item) {
  if (!arr.includes(item)) {
    arr.push(item);
  }
  return arr;
}

pushItem3(a, 1)
pushItem3(b, 11)

function pushItem4(arr, item) {
  if (!arr.includes(item)) {
    arr.push(item);
  }
  return arr;
}

pushItem4(