Adjusting JS code to Apps Script in Google sheet

Question

I have a working code in JS for my Web Application, which generates custom-format report ID number with the pattern NSAA-####-####-YYYY, where AA - any letter, #### any number, YYYY current year. This function in JS is quoted below.

I was asked to try to transfer the same functionality to Google sheet, as a "custom function."

Although most of the code works fine, I get issues with indexOf methods in GAS and overall I am not sure if I am doing it correctly at all. Would appreciate a quick hint on this.

This is JS code I am trying to reproduce in Apps Script:

let d = new Date();
const randomString = (length, chars) => {
  let mask = '';

  if (chars.indexOf('A') > -1) mask += 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  if (chars.indexOf('#') > -1) mask += '0123456789';
  let result = '';
  for (let i = length; i > 0; --i) result += mask[Math.round(Math.random() * (mask.length - 1))];
  return result;
}

// Inserting report ID into appropriate fields
const reportNS = () => {
  let reportIDNS = document.getElementById("reportIDNS");
  reportIDNS.value = 'NS' + randomString(2, 'A') + '-' + randomString(4, '#') + '-' + randomString(4, '#') + '-' +
    d.getFullYear();
}

My first idea was to put it in someting like this:

/**
 */

var d = new Date();
function randomString (length, chars) {
  var mask = '';

  if (chars.indexOf('A') > -1) mask += 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  if (chars.indexOf('#') > -1) mask += '0123456789';
  var result = '';

  for (var i = length; i > 0; --i)
    result += mask[Math.round(Math.random() * (mask.length - 1))];
  return result = 'NS' + randomString(2, 'A') + '-' + randomString(4, '#') + '-' + randomString(4, '#') + '-' + d.getFullYear();
}

However, I get the error

TypeError: Cannot call method "indexOf" of undefined.

Would appreciate a hint on this!

Answer 1

Got it - here how it works. Of course - need to use the second function to call that randomString:

// Funciton to create ReportID (or caseID) as the customer wants
function CaseID () {
  var d = new Date();
  var caseID = 'ID' + randomString(2, 'A') + '-' + randomString(4, '#') + '-' + randomString(4, '#') + '-' + d.getFullYear();
  return caseID;
} 

// Function that generates randomString - no surprises here
function randomString (length, chars) {
  var mask = '';

     if (chars.indexOf('A') > -1) mask += 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
     if (chars.indexOf('#') > -1) mask += '0123456789';
      var result = '';

  for (var i = length; i > 0; --i) {
    result += mask[Math.round(Math.random() * (mask.length - 1))]
  };
      return result;
 }