inheritance.js

// mostly stolen from http://phrogz.net/JS/classes/OOPinJS2.html

// first we define a mammal...
function Mammal(name) {
    this.name = name;
    this.offspring = [];
}
Mammal.prototype.haveABaby = function() {
    var newBaby = new Mammal("Baby " + this.name);
    this.offspring.push(newBaby);
    return newBaby;
}
Mammal.prototype.toString = function() { return '[Mammal "' + this.name + '"]'; }

// let's use our new class to describe some mammals!
var gerald = new Mammal("Gerald");
console.log("Gerald is " + gerald); // Gerald is [Mammal "Gerald"]

// But obviously we need to be more specific than this. How about a cat?
function Cat(name) {
    this.name = "Reverend Mc" + name;
}
Cat.prototype = new Mammal();
Cat.prototype.constructor = Cat; // otherwise Cats would have the constructor of Mammal
Cat.prototype.toString = function() { return '[Cat "' + this.name + '"]'; }

// so now we have cats, too.
var phil = new Cat("Phil");
console.log("Phil is " + phil); // Phil is [Cat "Reverend McPhil"]

// oh snap! Phil's actually a Phyllis!
var lilPhil = phil.haveABaby();
console.log('lilPhil is ' + lilPhil); // lilPhil is [Cat "Baby Reverend McPhil"]