Gerador CPF e CNPJ em Javascript

CPF.CPNJ_Generator.js

//es2015 syntaxe

console.clear();

String.prototype.repeat = String.prototype.repeat || function(n){ 
    return n<=1 ? this : (this + this.repeat(n-1)); 
}

String.prototype.padLeft = function(char, length) { 
    return char.repeat(Math.max(0, length - this.length)) + this;
}

let random = (min, max, pad) =>
  (~~(Math.random() * (max - min) + min))
    .toString()
    .padLeft((~~(Math.random() * (10))).toString(), pad);

function CPFGenerator(formated = false) {
  
  let calculateDig = (precpf) => {
    let len = precpf.length + 1;
    let numbers = precpf.split('').map((n) => parseInt(n));
    let sum = ((arr) => {
      let r = 0;
      for (var i = len; i >= 2; i--) {
        r += i * arr[len - i];
      }
      return r;
    })(numbers);
    
    let mod = sum % 11;
    let dig = mod < 2 ? 0 : 11 - mod;
    
    return precpf + dig;
  }
  
  let format = (cpf) => {
    let arr = cpf.split('');
    arr.splice(3, 0, ".");
    arr.splice(7, 0, ".");
    arr.splice(11, 0, "-");
    return arr.join('');
  }
  
  let cpf = "".concat(random(1, 1000, 3), random(0, 1000, 3), random(0, 1000, 3));
  cpf = calculateDig(calculateDig(cpf))

  return formated ? format(cpf) : cpf;
}

function CPNJGenerator(formated = false) {
  
  let calculateDig = (precnpj) => {
    let arr = precnpj.split('').map((n) => parseInt(n));
    let len = arr.length;
    let start = len == 12 ? 5 : 6;
    let first = true;
    let p = 0
    let sum = 0;
    for (var i = start; i > 1; i--) {
      sum += i * arr[p++]
      if (i == 2 && first) {
        i = 10; 
        first = false;
      }
    }
    let mod = sum % 11;
    let dig = mod < 2 ? 0 : 11 - mod;
    
    return precnpj + dig;
  }
  
  let format = (cnpj) => {
    let arr = cnpj.split('');
    arr.splice(2, 0, ".");
    arr.splice(6, 0, ".");
    arr.splice(10, 0, "/");
    arr.splice(15, 0, "-");
    return arr.join('');
  }
  
  let cpnj = "".concat(random(0,100, 2), random(0, 1000, 3), random(0, 1000, 3)) + "000" + (random(1, 4, 0));
  cpnj = calculateDig(calculateDig(cpnj))

  return formated ? format(cpnj) : cpnj;
 }

[...Array(10)].map((x, i) => {
  console.log(CPFGenerator(true))
});

[...Array(10)].map((x, i) => {
   console.log(CPNJGenerator(true))
});