index.js

/*!
 * randomatic <https://github.com/jonschlinkert/randomatic>
 *
 * Copyright (c) 2014-2017, Jon Schlinkert.
 * Released under the MIT License.
 */

'use strict';

var isNumber = require('is-number');
var typeOf = require('kind-of');
var mathRandom = require('math-random');

/**
 * Expose `randomatic`
 */

module.exports = randomatic;
module.exports.isCrypto = !!mathRandom.cryptographic;

/**
 * Available mask characters
 */

var type = {
  lower: 'abcdefghijklmnopqrstuvwxyz',
  upper: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
  number: '0123456789',
  special: '~!@#$%^&()_+-={}[];\',.'
};

type.all = type.lower + type.upper + type.number + type.special;

/**
 * Generate random character sequences of a specified `length`,
 * based on the given `pattern`.
 *
 * @param {String} `pattern` The pattern to use for generating the random string.
 * @param {String} `length` The length of the string to generate.
 * @param {String} `options`
 * @return {String}
 * @api public
 */

function randomatic(pattern, length, options) {
  if (typeof pattern === 'undefined') {
    throw new Error('randomatic expects a string or number.');
  }

  var custom = false;
  if (arguments.length === 1) {
    if (typeof pattern === 'string') {
      length = pattern.length;

    } else if (isNumber(pattern)) {
      options = {};
      length = pattern;
      pattern = '*';
    }
  }

  if (typeOf(length) === 'object' && length.hasOwnProperty('chars')) {
    options = length;
    pattern = options.chars;
    length = pattern.length;
    custom = true;
  }

  var opts = options || {};
  var mask = '';
  var res = '';

  // Characters to be used
  if (pattern.indexOf('?') !== -1) mask += opts.chars;
  if (pattern.indexOf('a') !== -1) mask += type.lower;
  if (pattern.indexOf('A') !== -1) mask += type.upper;
  if (pattern.indexOf('0') !== -1) mask += type.number;
  if (pattern.indexOf('!') !== -1) mask += type.special;
  if (pattern.indexOf('*') !== -1) mask += type.all;
  if (custom) mask += pattern;

  // Characters to exclude
  if (opts.exclude) {
    var exclude = typeOf(opts.exclude) === 'string' ? opts.exclude : opts.exclude.join('');
    exclude = exclude.replace(new RegExp('[\\]]+', 'g'), '');
    mask = mask.replace(new RegExp('[' + exclude + ']+', 'g'), '');
    
    if(opts.exclude.indexOf(']') !== -1) mask = mask.replace(new RegExp('[\\]]+', 'g'), '');
  }

  while (length--) {
    res += mask.charAt(parseInt(mathRandom() * mask.length, 10));
  }
  return res;
};