ES5 prototype inheritance

animals.js

function Animal(nickname, gender) {
    this.nickname = nickname;
    this.gender = gender;
}
Animal.prototype.getName = function () {
    return this.nickname;
};
Animal.prototype.getGender = function () {
    if (this.gender === "M") return "boy";
    if (this.gender === "F") return "girl";
}
Animal.prototype.greet = function () {
    var statement = "I'm " + this.getName() + " and I'm a " + this.getGender();
    console.log(statement);
};

function Cat(nickname, gender, ownerName) {
    Animal.call(this, nickname, gender);
    this.ownerName = ownerName;
}
Cat.prototype = (function () {
    // need value of `{ constructor: Cat, __proto__: Animal }`
    function CatExtendsAnimal() {}
    CatExtendsAnimal.prototype = Animal.prototype;
    var catPrototype = new CatExtendsAnimal();
    catPrototype.constructor = Cat;
    return catPrototype;
})();
Cat.prototype.meow = function () { console.log("meow") };
Cat.prototype.getName = function() {
    var originalName = Animal.prototype.getName.call(this);
    return this.ownerName + "'s " + originalName;
};

var c = new Cat("mittens", "F", "mike");
c.meow();
c.greet();
console.log(c.getName())

function Dog(nickname, gender, ownerName) {
    Animal.call(this, nickname, gender);
    this.ownerName = ownerName;
}
Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;
Dog.prototype.bark = function () { console.log("woof") };
Dog.prototype.getName = function () {
    var originalName = Animal.prototype.getName.call(this);
    return originalName + " the dog";
}
var d = new Dog("bobby", "M", "billy");
d.greet();

// ref:
// https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/Inheritance
// https://medium.com/developers-arena/javascript-classes-inheritance-and-prototype-chaining-es5-and-es6-way-4b8e9416702b
// https://medium.com/@dange.laxmikant/simplified-inheritance-in-js-es5-way-60b4ff19b008