credit card validator

credit.js

function validator(cardNumber){
const cardArray = cardNumber.toString().split("").map((e) => parseInt(e) )
  validlen(cardArray);
  const splitArr =  arrSplit(cardArray)
  const checksum = sumArrDigits(splitArr.arr1).reduce((a, c) => a + c) + splitArr.arr2.reduce((a, c) => a + c);

  if (checksum % 10 == 0){
    
    const typeValidatorArr = cardArray.slice(0,2)
    const typeValidatorInt = parseInt(typeValidatorArr.join(""))
    
    if (typeValidatorArr[0] == 4){
      return "VISA"
    }else if(typeValidatorInt == 34 || typeValidatorInt == 37){
      return "AMERICAN EXPRESS";
    }else if(typeValidatorInt == 22 || typeValidatorInt == 51 || typeValidatorInt == 52 || typeValidatorInt == 53 || typeValidatorInt == 54){
      return "MASTERCARD";
    }else if(typeValidatorInt == 35 ){
      return "JCB";
    }else if(typeValidatorInt == 60 ){
      return "DISCOVER";
    }else if(typeValidatorInt == 30 ){
      return "DINERS CLUB";
    }
  }
}
console.log(validator(cardNumber));

function sumArrDigits(array){
  return array.join("").split("").map(e => parseInt(e))
}

function validlen(arr){
  // checks for card length of 13, 15, or 16
  return  arr.length == 13  || arr.length == 15 || arr.length == 16
}

function arrSplit(cardArray){
  const selectOddValues = cardArray.filter((a,i)=>i%2 === 1);
  const selectEvenValues = cardArray.filter((a,i)=>i%2 === 0);
  let arr1;
  let arr2;
  if (cardArray.length % 2 == 1){
    arr1 = selectOddValues.map(e => e * 2);
    arr2 = selectEvenValues;
  }else {
    arr1 = selectEvenValues.map(e => e * 2);
    arr2 = selectOddValues;
  }
  return {arr1, arr2}
}