Add custom form validation

Wappler General How To
#1

Hi,
I am trying to add custom validation for a field in my form (UPC) because wappler doesn’t have any built in validation for this. But I am unable to find a way to do it through wappler.
Does wappler have any way that’ll allow me to add custom client side validation that’ll run with other available validations?
Thank you

#2

What would you like to validate? There’s a regex validation option, where you can enter any custom regexp pattern and validate the input.

#3

But my validation is little large, can it be done by regexp ? it is to validate the UPC.
Following is my code:

function validateUPC(barcode) {

    if (barcode.length < 8 || barcode.length > 18 ||
      (barcode.length != 8 && barcode.length != 12 &&
        barcode.length != 13 && barcode.length != 14 &&
        barcode.length != 18)) {
      return false;
    }

    var lastDigit = Number(barcode.substring(barcode.length - 1));
    var checkSum = 0;
    if (isNaN(lastDigit)) { return false; } // not a valid upc/ean

    var arr = barcode.substring(0, barcode.length - 1).split("").reverse();
    var oddTotal = 0, evenTotal = 0;

    for (var i = 0; i < arr.length; i++) {
      if (isNaN(arr[i])) { return false; } // can't be a valid upc/ean we're checking for

      if (i % 2 == 0) { oddTotal += Number(arr[i]) * 3; }
      else { evenTotal += Number(arr[i]); }
    }
    checkSum = (10 - ((evenTotal + oddTotal) % 10)) % 10;

    // true if they are equal
    return checkSum == lastDigit;
  }