oop.js

/*
  OOP modeling
*/

//class
function Man(firstName, secondName, age, sex) {
  //public
  this.firstName = firstName;
  this.secondName = secondName;
  this.age = age || 0;
  this.sex = sex;
};

//static final
Man.SexEnum = {
  MALE : 'male',
  FEMALE : 'female'
};
Object.freeze(Man.SexEnum);

Man.prototype = {
  fullName : function () {
    return this.firstName + ' ' + this.secondName;
  }
}

var male = new Man('first', 'second', 10, Man.SexEnum.MALE);

//Female extends Man
function Female(firstName, secondName, age) {
  Man.call(this, firstName, secondName, age, Man.SexEnum.FEMALE);
};

var female = new Female('first', 'second', 18);
console.log(female);