Implementing Inheritance in JavaScript

Below example explains to build functions in a class and also implementing the inheritance.

if (typeof Test == 'undefined')

    Test = {};

Test.namespace = function (nmspace) {

    var nms = nmspace.split(".");

    var obj = Test;

    for (i = 0; i < nms.length; i++) {

        obj[nms[i]] = (obj[nms[i]]) ? obj[nms[i]] : {};

        obj = obj[nms[i]];

    }

}

Test.namespace("App.UI");

The above lines would help in creating namespaces and there after the functions are defined under specific namespace.

Test.App.UI.Base = function () {

    alert('parent class constructor');

}

Test.App.UI.Base.prototype.setInnerText = function (id, txt) {

    document.getElementById(id).innerText = txt;

}

Above functions are in class “Base” which falls in “Test.App.UI” namespace.

var objTest;

function LoadTest() {

    objTest = new Test.App.UI.Test();

}

Test.App.UI.Test = function () {

    Test.App.UI.Test.superclass.constructor.call(this, Test.App.UI.Base);

}

//calling below function will apply the iheritance

Test.extend(Test.App.UI.Test, Test.App.UI.Base);

Test.App.UI.Test.prototype.Hello = function () {

    alert(“hello”)

}

Test.App.UI.Test.prototype.SetValue = function (val) {

    objTest.setInnerText('lbl', resp.value);

}

Above functions are in“Test” class which also falls in “Test.App.UI” namespace.

Test.extend = function (subclass, superclass) {

    var fun = function () { };

    fun.prototype = superclass.prototype;

    subclass.prototype = new fun();

    subclass.prototype.constructor = subclass;

    subclass.superclass = superclass.prototype;

}

Test.extend function is used to apply the inheritance for the given two classes.