javascript object, class & inheritance, sigletons

 

•Class & Inheritance

 

•Class & Inheritance

–-Prototypal Inheritance

var oldObject = {     firstMethod: function () { alert("first"); },     secondMethod: function () { alert("second"); } }; var newObject = new Object(oldObject); newObject.thirdMethod = function () { alert("third"); }; var myDoppelganger = new Object(newObject); myDoppelganger.firstMethod(); // or myDoppelganer[“firstMethod”]();

var obj1 = function () { this.title = "obj1"; } var obj2 = function () {} obj2.prototype = new obj1; var obj2Class = new obj2(); alert(obj2Class.title); obj1 = { title:"obj1_" } obj2 = new Object(obj1); alert(obj2.title);

 

–-Method apply (Member variable)

§Function.apply(thisArg[, argArray])

–function Car(make, model, year) {

–  this.make = make;

–  this.model = model;

–  this.year = year;

–}

– 

–function RentalCar(carNo, make, model, year) {

–  this.carNo = carNo;

–  Car.apply(this, new Array(make, model, year));

–}

– 

–myCar = new RentalCar(2134,"Ford","Mustang",1998);

–document.write("Your car is a " + myCar.year + " " + myCar.make + " " + myCar.model + ".");

 

–-Method apply (Member function)

§function TopClass (name, value) {

§ this.name = name;

§ this.value = value;

§ this.getAlertData = function () {

§ alert(this.name);

§ alert(this.value);

§ }

§}

§function SubClass (name, value, dept) {

§ this.dept = dept;

§ TopClass.apply(this, arguments);

§ this.getView = function () {

§ this.getAlertData();

§ }

§}

§//SubClass.prototype = new TopClass();

§var objSubClass = new SubClass("상위클래스","super","community");

§objSubClass.getView();

 

–-Method call

§Function.call(thisArg[, arg1[, arg2[, ...]]])

–function car(make, model, year) {

–    this.make = make, this.model = model, this.year = year;

–}

– 

–function hireCar(carNo, make, model, year) {

–    this.carNo = carNo, car.call(this, make, model, year);

–}

 

•-Prototype

–Profiler = function () {..}

–Profiler.prototype.name = function () {..}

•-Namespace

–YAHOO = {};

•-new operator

–function object(o) {

– function F() {};

– F.prototype = o;

– return new F();

–}

–classA = new Profiler(); or classA = object(Profiler);

 

-Encapsulate (Parasitic)

YAHOO = {}; YAHOO.Trivia = function () {     var privateVar = "showPoser";     function privateNextPoser() {         alert("getNextPoser");     }     return {         getNextPoser: function (cat, diff) {             privateNextPoser();         },         showPoser: function () {             alert(privateVar);         }     }; } (); function getFunc() { var oObj = YAHOO.Trivia; oObj.getNextPoser(); }

YAHOO = {}; YAHOO.Trivia = function () {     var privateVar = "showPoser";     function privateNextPoser() {         alert("getNextPoser");     }     return {         getNextPoser: function (cat, diff) {             privateNextPoser();         },         showPoser: function () {             alert(privateVar);         }     }; }; function getFunc() { var oObj = new YAHOO.Trivia(); oObj.getNextPoser(); }

 

-Singletons

var singleton = function () {

    var privateVariable;

    function privateFunction(x) {

        ...privateVariable...

    }

    return {

        firstMethod: function (a, b) {

            ...privateVariable...

        },

        secondMethod: function (c) {

            ...privateFunction()...

        }

    };

}();