function User ( name, username ) {

  var password = User.generatePassword(15);

  this.name = name;
  this.username = username;
  this.password = User.encryptPassword( password );

  console.log("Your password is : " + password)
}

User.randomChar = function() {
  var chars = "abcdefghijklmnopqrstxyz";
  var numChars = chars.length;
  var randomCharPos = Math.round(Math.random()*numChars)
  return chars[randomCharPos];
}

User.generatePassword = function( passwordLentgth ) {
  return Array(passwordLentgth)
          .fill(0)
          .map( function() {
            return User.randomChar()
          })
          .join("")
}

User.encryptPassword = function( password ) {
  var codes = { a: "4", e: "3", i: "1", o: "0", u: "2" }
  return password
          .split("")
          .map( function(elem) {
            return codes[elem] || elem;
          })
          .join("");
}

User.prototype.decryptPassword = function() {
  var codes = ["o","i","u","e","a"]
  return this.password
            .split("")
            .map( function(elem) {
              return codes[elem] || elem;
            }).join("");
}

var me = new User("JuanMa", "juanmaguitar")