Random Password Generator

passwordGenerator.js

/**
 * Generate string from ascii range
 * @param {any} ranges - ASCII code
 * @param {number} charsCount
 * @param {string[]} allCharsTotal
 * @return {string}
 */
function generateChars(ranges, charsCount, allCharsTotal) {
  var allChars = [];
  var i;
  ranges.map(function (range) {
    for (i = range.min; i <= range.max; i++) {
      allChars.push(String.fromCharCode(i).toString());
      allCharsTotal.push(String.fromCharCode(i).toString());
    }
  });

  return allChars
    .sort(function () {
      return Math.random() - Math.random();
    })
    .slice(0, charsCount)
    .join('');
}

/**
 * Shuffle string
 * @param {string} str
 * @return {string}
 */
function shuffle(str) {
  var parts = str.split('');
  var random;
  var temp;
  var i;
  for (i = parts.length; i > 0; ) {
    random = parseInt(Math.random() * i, 10);
    temp = parts[--i];
    parts[i] = parts[random];
    parts[random] = temp;
  }
  return parts.join('');
}

/**
 * Generate a random password string. All parameters are optional. By default it generates 20 character long string from the ASCII table
 * @param {number} [fixedLength] - Set password length. Default is 20 characters if parameter is not used.
 * @param {number} [minLength] - For random size password, min size. Good to set at least 20
 * @param {number} [maxLength] - For random size password, max size. Good to set some where between 20 and 123
 * @param {boolean | string | number} [noSpecial] - Set truthie to disable special characters in password
 * @param {boolean | string | number} [noNumber] - Set truthie to disable numbers in password
 * @param {boolean | string | number} [noUpper] - Set truthie to disable capital letters in password
 * @param {boolean | string | number} [noLower] - Set truthie to disable lowercase letters in password
 * @return {string} - password
 */
function passwordGenerator(
  fixedLength,
  minLength,
  maxLength,
  noSpecial,
  noNumber,
  noUpper,
  noLower
) {
  var allCharsTotal = [];
  var pwLength =
    fixedLength || Math.floor(Math.random() * (maxLength - minLength + 1)) + minLength || 20;
  var types = [
    { type: 'lower', enabled: !noLower, ranges: [{ min: 97, max: 122 }] },
    { type: 'upper', enabled: !noUpper, ranges: [{ min: 65, max: 90 }] },
    { type: 'number', enabled: !noNumber, ranges: [{ min: 48, max: 57 }] },
    {
      type: 'special',
      enabled: !noSpecial,
      ranges: [
        { min: 33, max: 47 },
        { min: 58, max: 64 },
        { min: 91, max: 96 },
        { min: 123, max: 126 },
      ],
    },
  ];
  var enabledTypes = types.filter(function (obj) {
    return obj.enabled;
  });
  var charsCount = Math.floor(pwLength / enabledTypes.length);

  var charStr = enabledTypes
    .map(function (i) {
      return generateChars(i.ranges, charsCount, allCharsTotal);
    })
    .join('');

  // if password is not long enough, add extra characters
  while (charStr.length !== pwLength) {
    charStr += allCharsTotal
      .join('')
      .charAt(Math.floor(Math.random() * allCharsTotal.join('').length));
  }
  return shuffle(charStr);
}

var pw = passwordGenerator(0, 20, 123);

console.log(pw);