text: /**
   * https://github.com/vczero/guid/blob/master/guid.js
   * guid: we can use to create token or id...
   * Inspired from the book of JavaScript Patterns, Stoyan Stefanov
   * You can add some special value in this guid, such as user's email or nickname or id.
   * For example, I added a ObjectId(mongoDB) to this guid in my project.
   * @module guid
   */
  
  var crypto = require('crypto');
  
  module.exports = {
  
    guid: function() {
      return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random() * 16 | 0,
          v = c == 'x' ? r : (r & 0x3 | 0x8);
        return v.toString(16);
      }).toUpperCase();
    },
  
    md5: function(password){
      var md5 = crypto.createHash('md5');
      var salt = '(!%$88hs@gophs*)#sassb9';
      var newPwd = md5.update(password + salt).digest('hex');
      return newPwd;
    },
  
    getKey: function(){
      return 'HSHHSGSGGSTWSYWSYUSUWSHWBS-REACT-NATIVE';
    }
  
  };