Javascript inheritance(prototype)

gistfile1.js

Object.make = function make (proto) {
    var o = Object.create(proto);
    var args = [].slice.call(arguments, 1);
    args.forEach(function (obj) {
        Object.getOwnPropertyNames(obj).forEach(function (key) {
            o[key] = obj[key];
        });
    });
    return o;
}

Base = function(param){
    this.init(param);
}
Base.prototype = {
    init: function(param){
        this.param = param;
    },
    calc: function(){
        var result = this.param * 10;
        document.write("Result from calc in Base: " + result + "<br/>");
    },
    calcB: function(){
        var result = this.param * 20;
        document.write("Result from calcB in Base: " + result+ "<br/>");
    }
}
    
Extend = function(param){
    this.init(param);
}
Extend.prototype = Object.make(Base.prototype, {
    constructor: Extend,
    calc: function(){
        var result = this.param * 50;
        document.write("Result from calc in Extend: " + result+ "<br/>");
    }
});

    
extendedObj = new Extend(10);
extendedObj.calc();
extendedObj.calcB();​