jsPatterns.klass.js - the ultimate imitation for class.

jsPatterns.klass.js

var klass = function (Parent, props) {
    var Child, F, i;
    // 1.
    // new constructor
    Child = function () {
        if (Child.uber && Child.uber.hasOwnProperty("__construct")) {
            Child.uber.__construct.apply(this, arguments);
        }
        if (Child.prototype.hasOwnProperty("__construct")) {
            Child.prototype.__construct.apply(this, arguments);
        }
    };
    // 2.
    // inherit
    Parent = Parent || Object;

    F = function () {};
    F.prototype = Parent.prototype;
    Child.prototype = new F();
    Child.uber = Parent.prototype;
    Child.prototype.constructor = Child;
    // 3.
    // add implementation methods
    for (i in props) {
        if (props.hasOwnProperty(i)) {
            Child.prototype[i] = props[i];
        }
    }
    // return the "class"
    return Child;
};

//test
var Man = klass(null, {
    __construct: function (what) {
        console.log("Man's constructor");
        this.name = what;
    },
    getName: function () {
        return this.name;
    }
});

var first = new Man('Adam'); // logs "Man's constructor"
first.getName(); // "Adam"

var SuperMan = klass(Man, {
    __construct: function (what) {
        console.log("SuperMan's constructor");
    },
    getName: function () {
        var name = SuperMan.uber.getName.call(this);
        return "I am " + name;
    }
});

var clark = new SuperMan('Clark Kent');
clark.getName(); // "I am Clark Kent"