javascript

Class Prototypes
Chapter 22: The Evolution of JavaScript
You can force a method to be declared on the prototype, and therefore shared amongst instances, by
using the prototype attribute as shown here:
class Person {
}
//private properties
private var personName: String;
private var personAge: Number;
//constructor
function Person(name: string, age: int){
personName = name;
personAge = age;
}
//public function
prototype function sayAge(){
alert(personAge);
}
This modification defines the sayAge() method on Person.prototype instead of creating a new
version for each instance. The instances of Person all have access to sayAge() on the prototype and
will benefit from its use of the this object for late binding of the object being used.
Virtual Properties
Virtual properties are defined by providing getters and/or setters for a specific property name. Instead
of being a true property, which simply stores data, virtual properties may perform some additional
processing when the property is accessed before determining an action to take. Getters and setters are
defined via function get and function set as part of the class definition, as shown in this example:
class Person {
//private properties
private var personName: String;
private var personAge: Number;
//constructor
function Person(name: string, age: int){
personName = name;
personAge = age;
}
//name property
function get name(): string{
return personName;
(continued)
727