defineRegExpCode.js

let responseDadosBoleto = {
  quantidadeBoleto: "2",
  boleto01: { valor: "R$59,90", vencimento: "12/12/2022", codigo: "36490.00084 00031.521305 00003.127941 5 00000000005990", id: "1453417" },
  boleto02: { valor: "R$59,90", vencimento: "10/01/2023", codigo: "36490.00043 00031.521305 00003.377637 3 00000000005990", id: "1491289" },
};

if (responseDadosBoleto.quantidadeBoleto == 1) {
  let code = responseDadosBoleto.codigo;
  code = replaceAll(code, " ", "");
  code = replaceAll(code, ".", "");
  let result = [];
  result.push(generateRegex(code));
  console.log(result[0]);
  return result;
}
if (responseDadosBoleto.quantidadeBoleto > 1) {
  var properties = Object.keys(responseDadosBoleto);
  var newObject = { boletos: [] };
  for (let k = 1; k < properties.length; k++) {
    newObject.boletos.push(responseDadosBoleto[properties[k]]);
  }
  let dadosBoleto = newObject;


  let result = [];
  for (let i = 0; i < responseDadosBoleto.quantidadeBoleto; i++) {
    let code = dadosBoleto.boletos[i].codigo;
    code = code.replaceAll(".", "");
    code = code.replaceAll(" ", "");

    result.push(generateRegex(code));
  }
  console.log(result);
  return result;
}

function checkNextChar(list, i, char) {
  if (list[i + 1] == char) {
    return true;
  }

  return false;
}
function replaceAll(text, value, replacer) {
  while (text.includes(value)) {
    text = text.replace(value, replacer);
  }
  return text;
}
function generateRegex(code) {
  let groups = [];
  for (let i = 0; i < code.length; i++) {
    let chars = [];
    if (code[i] == "0") {
      while (checkNextChar(code, i, "0")) {
        chars.push(code[i]);
        i++;
      }
      chars.push(code[i]);

      let zeroGroup = chars.join("");

      if (zeroGroup.length > 3) {
        groups.push(`0{${zeroGroup.length - 1},${zeroGroup.length}}`);
        continue;
      } else {
        groups.push(code[i]);
        continue;
      }
    }
    groups.push(code[i]);
  }
  return groups.join("");
}