js assigns consecutive ids to find the smallest missing number in consecutive numbers in the array

export function setID(state,arr) {
console.log(arr)
  if(arr.length===0){
    return '1'
  }
  if (Math.max(...arr) - Math.min(...arr) < arr.length) {
    return String(arr.length + 1);
  } else {
    arr = arr.sort();

    let id = "";
    for (let i = 0; i < arr.length; i++) {
      if (arr[i] > i + 1) {
        id = String(i + 1);
        return id;
      }
    }
  }
}