cpf-utility.ts

class CPF {
  static CPF_MASK = '$1.$2.$3-$4';
  static CPF_REGEX = /(\d{3})(\d{3})(\d{3})(\d{2})/;

  static generateFormated(): string {
    return this.format(this.generate());
  }

  static format(cpf: string): string {
    return cpf.replace(this.CPF_REGEX, this.CPF_MASK);
  }

  static removeFormatting(cpf: string): string {
    return cpf.replace(/[-\.]/g, '');
  }

  static generate(): string {
    const randomNumber = (Math.random() * 1_000_000_000).toString();
    const integerString = parseInt(randomNumber).toString();
    let _cpf = integerString.padStart(9, '0');
    for (let digit = 0; digit < 100; digit++) {
      const verifierDigit = digit.toString().padStart(2, '0');
      if (this.isValid(_cpf + verifierDigit))
        return _cpf += verifierDigit;
    }
    return _cpf;
  }

  static isValid(cpf: string): boolean {
    const _cpf = this.removeFormatting(cpf);
    let sum = 0, rest;
    const ALL_DIGITS_ARE_THE_SAME = _cpf.split('')
      .every(digit => digit === _cpf[0]);
    if (ALL_DIGITS_ARE_THE_SAME)
      return false;
    for (let i = 1; i<= 9; i++)
      sum += parseInt(_cpf.substring(i - 1, i)) * (11 - i);
    rest = (sum * 10) % 11;
    if ((rest === 10) || (rest === 11)) rest = 0;
    if (rest !== parseInt(_cpf.substring(9, 10)))
      return false;
    sum = 0;
    for (let j = 1; j <= 10; j++)
      sum += parseInt(_cpf.substring(j - 1, j)) * (12 - j);
    rest = (sum * 10) % 11;
    if ((rest == 10) || (rest == 11)) rest = 0;
    if (rest != parseInt(_cpf.substring(10, 11)))
      return false;
    return true;
  }
}