Javascript Password Generator Invalid return statement

We are using Camunda to produce a password using some code we found here on StackOverflow.

This code was working but all of the sudden we started getting and error;

Invalid return statement return

Can someone help me out?

Thanks

function generatePassword(length, rules) {
    if (!length || length == undefined) {
        length = 10;
    }

    if (!rules || rules == undefined) {
        rules = [
            {chars: "abcdefghijklmnopqrstuvwxyz", min: 3},  // As least 3 lowercase letters
            {chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZ", min: 3},  // At least 2 uppercase letters
            {chars: "0123456789", min: 2},                  // At least 2 digits
            {chars: "!@#$&*?|%+-_./:;=()[]{}", min: 2}      // At least 1 special char
        ];
    }

    var allChars = "", allMin = 0;
    rules.forEach(function(rule) {
        allChars += rule.chars;
        allMin += rule.min;
    });
    if (length < allMin) {
        length = allMin;
    }
    rules.push({chars: allChars, min: length - allMin});
    
    var pswd = "";
    rules.forEach(function(rule) {
        if (rule.min > 0) {
            pswd += shuffleString(rule.chars, rule.min);
        }
    });
    
    return shuffleString(pswd);
}

function shuffleString(str, maxlength) {
    var shuffledString = str.split('').sort(function(){return 0.5-Math.random()}).join('');
    if (maxlength > 0) {
        shuffledString = shuffledString.substr(0, maxlength);
    }
    return shuffledString;
}

var pswd = generatePassword(15, [
  {chars: "abcdefghijklmnopqrstuvwxyz", min: 4},  // As least 4 lowercase letters
  {chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZ", min: 1},  // At least 1 uppercase letters
  {chars: "0123456789", min: 3},                  // At least 3 digits
  {chars: "!@#$&*?|%+-_./:;=()[]{}", min: 2}      // At least 2 special chars
]);

return generatePassword();