Playing with classes and inheritance

base.js

/*
 * This has essentially turned into Resig's Simple JavaScript Inheritance
 * with some minor modifications for class names and use strict,
 * and getters ans setters
 * http://ejohn.org/blog/simple-javascript-inheritance/
 * http://ejohn.org/blog/javascript-getters-and-setters/
 */
(function (window) {
  
  "use strict";

  // function test
  var _fnTest = /xyz/.test(function(xyz){}) ? /\b_super\b/ : /.*/;
      
  // no operation
  var _noop = function () {};
    
  // super methods
  var _makeSuper = function (name, method, proto) {
    return function () {
      var tmp = this._super;
      this._super = proto[name] || _noop;        
      var ret = method.apply(this, arguments);        
      this._super = tmp;        
      return ret;        
    };
  };
  
  // the Base constructor for all classes
  var Base = window.Base = function Base () {};
  
  Base.extend = function (name, settings) {
    var props = settings || {};
    
    // prototypical inheritance
    Base._extending = true;
    var proto = new this();
    Base._extending = false;
      
    // add properties to prototype
    var i, g, s;
    for (i in props) {
      if (props.hasOwnProperty(i)) {        
        if (typeof props[i] === "function" && _fnTest.test(props[i])) {
          proto[i] = _makeSuper(i, props[i], this.prototype);
        } else {
          g = props.__lookupGetter__(i);
          s = props.__lookupSetter__(i);
          if (g || s) {
            if (g) proto.__defineGetter__(i, g);
            if (s) proto.__defineSetter__(i, s);
          } else {
            proto[i] = props[i];
          }
        }
      }
    }
    
    // constructor
    var Class = function Class () {
      if (!Base._extending && this.initialize) {
        this.initialize.apply(this, arguments);
      }
    };
    
    // add extensibility
    Class.extend = Base.extend;
    
    // return constructor
    Class.prototype = proto;
    Class.prototype._class = name;
    Class.prototype.constructor = Class;
    return Class;
  };
  
})(this);

test.js

(function (window) {
  
  "use strict";

  var Base = window.Base;

  var Person = Base.extend("Person", {
    initialize: function (name) {
      this.name = name;
      this.points = 100;
      this.alive = true;
    },
    speak: function (text) {
      console.log(text + " I am a " + this._class + "!");
    },
    damage: function (points) {
      this.points += points;
      if (this.points <= 0) {
        this.die();
      }
    },
    die: function () {
      this.alive = false;
      this.points = 0;
      console.log(this.name + ", " + this + ", is dead.");
    },
    toPrimitive: function () {
      return this._class;
    },
    toString: function () {
      return this.toPrimitive();
    },
    valueOf: function () {
      return this.toPrimitive();
    }
  });
  
  var Ninja = Person.extend("Ninja", {
    initialize: function (name) {
      this._super(name);
      this.points += 20;
    },
    chop: function (person) {
      person.damage(-25);
    }
  });
  
  var Samurai = Ninja.extend("Samurai", {
    initialize: function (name) {
      this._super(name);
      this.points += 50;
    },
    slice: function (person) {
      person.damage(-50);
    }
  });
  
  var matthew = new Samurai("Matthew");
  var michael = new Ninja("Michael");
  
  console.log(matthew, michael);
  
})(this);