ChatGPT: Create a javascript function that receive a string and return the next string using only the following chars "346789ABCDEFGHJKLMNPQRTUVWXYZ". Example: for string "3" the next is "4". For string "34" the next is "36". For string "AAAA" the next is "AAAB". For string "AAAZ" the next is "AAB3".

nextString.js

function nextString(str) {
  let chars = "346789ABCDEFGHJKLMNPQRTUVWXYZ";
  let result = "";
  let carry = true;

  for (let i = str.length - 1; i >= 0; i--) {
    let index = chars.indexOf(str[i]);

    if (carry && index < chars.length - 1) {
      result = chars[index + 1] + result;
      carry = false;
    } else if (carry && index === chars.length - 1) {
      result = chars[0] + result;
      carry = true;
    } else {
      result = str[i] + result;
    }
  }

  return carry ? chars[0] + result : result;   // If there is a carry, add a '1' to the beginning of the string. Otherwise, return the string as is.  
}