password-maker/lib/index.js

Generate a password randomly

"use strict";

var ASCII_TABLE = {
  lowercase : {
    start: 97,
    end  : 122
  },
  uppercase : {
    start: 65,
    end  : 90
  },
  number : {
    start: 48,
    end  : 57
  },
  symbol : {
    start: 33,
    end  : 47
  }
};

var generateNumber = function(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

function generatePassword(pOptions, pLength) {
  var length  = 10;
  var options = {
    uppercase : true,
    symbols   : true,
    numbers   : true
  };

  if (pOptions instanceof Object) {
    options.uppercase = ('uppercase' in pOptions) ? pOptions.uppercase : options.uppercase;
    options.symbols   = ('symbols' in pOptions) ? pOptions.symbols : options.symbols;
    options.numbers   = ('numbers' in pOptions) ? pOptions.numbers : options.numbers;
  } else {
    pLength = pOptions;
  }

  if (!isNaN(parseFloat(pLength)) && isFinite(pLength)) {
    length = Math.max(4, Math.floor(pLength));
  }

  // Generated password
  var output    = [];

  // List of available indexes that could be used
  var available = [];

  // Count number of reserved char to fill the requirement
  var reservedChars = 1 + ((options.uppercase || 0 ) && 1) +
                          ((options.symbols   || 0 ) && 1) +
                          ((options.numbers   || 0 ) && 1);

  for(var index = 0; index < length; ++index) {
    output.push(String.fromCharCode(generateNumber(ASCII_TABLE.lowercase.start, ASCII_TABLE.lowercase.end)));
    available.push(index);
  }

  var fillRequirement = function(asciiType) {
    var numberOfType = generateNumber(1, (length - reservedChars + 1));

    for (index = 0; index < numberOfType; ++index) {
      var max         = available.length - 1;
      var chr         = String.fromCharCode(generateNumber(asciiType.start, asciiType.end));
      var randomIndex = generateNumber(0, max);
      var chrIndex    = available[randomIndex];

      output[chrIndex] = chr;
      available[randomIndex] = available[max];
      available.length = max;
    }

    length -= numberOfType;
    reservedChars--;
  };

  if (options.uppercase) {
    fillRequirement(ASCII_TABLE.uppercase);
  }

  if (options.symbols) {
    fillRequirement(ASCII_TABLE.symbol);
  }

  if (options.numbers) {
    fillRequirement(ASCII_TABLE.number);
  }

  return output.join('');
}

module.exports = generatePassword;
module.exports.generatePassword = generatePassword;