Functions to generate Brazil's Document validator number - CPF / CNPJ

docValidationHelper.js

/**
 * Receives a part of the document and returns a validation digit
 * Used mostly for CPF or CNPJ
 *
 * Ex.:
 * getVerificationDigit("000000001") // 9
 * getVerificationDigit("0000000019") // 1
 * getVerificationDigit("100200300") // 8
 * getVerificationDigit(1, 9) // 9
 * getVerificationDigit(19, 9) // 1
 * @param partialDoc String|Number - the document number
 * @param minLen Number - how many digits are expected (in case the doc was parsed from a string with leading zeros)
 * @returns Number
 */
function getVerificationDigit(partialDoc, minLen) {
  const str = partialDoc.toString();
  let len = str.length;
  if (minLen) {
    len = minLen;
  }
  let digit = str.split("").reduce((all, digit, index) => {
    return all + digit * (len + 1 - index);
  }, 0);
  digit = 11 - (digit % 11);
  if (digit > 9) digit = 0;

  return digit;
}

/**
 * Removes ".", "-", "/" and anything else that is not a number from the document
 *
 * Ex.:
 * parseDoc("000.000.001-91") // 191
 * parseDoc("192.168.0.1") // 19216801
 * @param strDoc String - The document with all visual aid characters
 * @returns Number
 */
function parseDoc(strDoc) {
  const strDocOnlyNumbers = (strDoc + "").replace(/[^0-9]/gi, "");
  return parseInt(strDocOnlyNumbers);
}

/**
 * Adds ".", "-", "/" and other aiding characters to a document.
 * The character "0" in format will be replaced by the corresponding
 * number at the same index in intDoc, traversing from the last to
 * the first character in format.
 *
 * Ex.:
 * formatDoc(191, "000.000.000-00") // "000.000.001-91"
 * formatDoc(11122233300, "000.000.000-00") // "111.222.333-00"
 * formatDoc(123456, "0 / 0 [0,0]") // "3 / 4 [5,6]"
 * formatDoc(999, "0 / 0 [0,0]") // "0 / 9 [9,9]"
 * @param intDoc Number - The document as a number
 * @param format String - Format that will receive the numbers of the doc
 * @returns String
 */
function formatDoc(intDoc, format) {
  const strDoc = intDoc.toString();
  let pos = strDoc.length;
  return format
    .split("")
    .reverse()
    .map((fChar) => {
      if (fChar === "0") {
        pos -= 1;
        if (pos < 0) {
          return fChar;
        } else {
          return strDoc.charAt(pos);
        }
      } else {
        return fChar;
      }
    })
    .reverse()
    .join("");
}

/**
 * Generates a random document number with a specific length.
 *
 * Ex.:
 * generateRandomDoc(9) // "523784190"
 * generateRandomDoc(9) // "154768391"
 * generateRandomDoc(3) // "110"
 * @param length Number - how many chars should the doc have
 * @returns String - a string of numbers with the provided length
 */
function generateRandomDoc(length) {
  return Array(length)
    .fill("")
    .map(() => Math.round(Math.random()))
    .join("");
}

/**
 * Adds the verification digits to the document and returns the whole string.
 *
 * Ex.:
 * addVerificationDigits("000000001", 2) // "00000000191"
 * addVerificationDigits("100200300", 2) // "10020030088"
 * @param doc String|Number - the document. Must be a string because of the leading zeros
 * @param amount Number - How many digits to add
 */
function addVerificationDigits(doc, amount) {
  let newDoc = doc.toString();
  for (let i = 0; i < amount; i++) {
    newDoc = newDoc + "" + getVerificationDigit(newDoc);
  }
  return newDoc;
}

/**
 * Checks if the document string is valid
 *
 * Ex.:
 * validateDoc("00000000191", 2) // true
 * validateDoc("00000000155", 2) // false
 * validateDoc("10020030088", 2) // true
 * 
 * If passing digits as null or 0, will always return isValid=true
 *
 * If using debug=true, will return an object with more info:
 * validateDoc("00000000155", 2, true) // {doc: '00000000155', partial: '000000001', compare: '00000000191', isValid: false }
 * @param doc String
 * @param digits Number - default 2
 * @param debug Boolean - default false - if true, the return value will be an object
 * @returns Boolean - true or false, or Object({ doc, partial, compare, isValid }) if debug=true
 */
function validateDoc(doc, digits = 2, debug = false) {
  const partialDoc = (digits === null || digits === 0)
    ? doc.toString()
    : doc.toString().slice(0, digits * -1);
  const compareDoc = addVerificationDigits(partialDoc, digits);
  const isValid = doc === compareDoc;
  if (debug) {
    return { doc, partial: partialDoc, compare: compareDoc, isValid };
  }
  return isValid;
}

// validateCPF("000.000.001-91") // {valid: true, formatted: '000.000.001-91'}
// validateCPF("000000001-91") // {valid: true, formatted: '000.000.001-91'}
// validateCPF(00000000191) // {valid: true, formatted: '000.000.001-91'}
// validateCPF(191) // {valid: true, formatted: '000.000.001-91'}
// validateCPF("000.000.001-55") // {valid: false, formatted: '000.000.001-55'}
// validateCPF("155") // {valid: false, formatted: '000.000.001-55'}
// validateCPF("19") // {valid: false, formatted: '000.000.000-19'}
function validateCPF(CPF) {
  const doc = parseDoc(CPF);
  const docZero = doc.toString().padStart(11, "0");
  const valid = validateDoc(docZero, 2);
  const formatted = formatDoc(doc, "000.000.000-00");

  return { valid, formatted };
}

// validateCNPJ("00.000.000/0001-91") // { valid: true, formatted: '00.000.001/0001-36'}
// validateCNPJ("00.000.001/0001-36") // { valid: true, formatted: '00.000.001/0001-91'}
// validateCNPJ(191) // {valid: true, formatted: '00.000.000/0001-91'}
// validateCNPJ(1000136) // {valid: true, formatted: '00.000.001/0001-36'}
// validateCNPJ("12312312312") // {valid: false, formatted: '00.012.312/3123-12'}
function validateCNPJ(CNPJ) {
  const doc = parseDoc(CNPJ);
  const docZero = doc.toString().padStart(14, "0");
  const valid = validateDoc(docZero, 2);
  const formatted = formatDoc(doc, "00.000.000/0000-00");

  return { valid, formatted };
}

getAllPossibleDocs.js

/**
 * Gets a part of a document and generates all possible full documents
 *
 * Ex.:
 * getAllPossibleDocs("123.***.789-**", 2) // Array[100] like ["123.000.789-02", "123.001.789-58"]
 * @param part String - what part of the doc you have, and the rest filled with "*"
 * @param digits Number - how many chars of the "part" are the verification digits, counting from the end
 * @param format String - how to format the returning value
 * @param start Number - paginate results, starting index
 * @param limit Number - paginate results, max return size
 */
function getAllPossibleDocs({ part, digits, format, start = 0, limit }) {
  const paramDoc = part.toString().replace(/[^0-9*]/gi, "");
  const wildChars = paramDoc.replace(/[^*]/gi, "").length;
  const possibilities = 10 ** wildChars;
  // console.log({ paramDoc, wildChars, possibilities, start, limit })

  const res = [];
  for (let idx = start; idx < possibilities; idx++) {
    const strIdx = idx.toString().padStart(wildChars, "0");
    let pos = strIdx.length;
    const doc = paramDoc
      .split("")
      .reverse()
      .map((fChar) => {
        if (fChar === "*") {
          pos -= 1;
          return pos < 0 ? "0" : strIdx.charAt(pos);
        } else {
          return fChar;
        }
      })
      .reverse()
      .join("");
    const isValid = validateDoc(doc, digits)

    // console.log(idx, strIdx, doc, formatDoc(doc, format), isValid);

    if (isValid) {
      if (format) {
        res.push(formatDoc(doc, format));
      } else {
        res.push(doc);
      }
    }
    if (limit != null && res.length >= limit) break;
  }

  return res;
}