javascript

Chapter 7: Anonymous Functions
A privileged method is a public method that has access to private variables and/or private functions. There
are two ways to create privileged methods on objects. The first is to do so inside a constructor, as in this
example:
function MyObject(){
//private variables and functions
var privateVariable = 10;
function privateFunction(){
return false;
}
}
//privileged methods
this.publicMethod = function (){
privateVariable++;
return privateFunction();
};
This pattern defines all private variables and functions inside the constructor. Then privileged methods
can be created to access those private members. This works because, when defined in the constructor, the
privileged methods become closures with full access to all variables and functions defined inside the
constructor ’ s scope. In this example, the variable privateVariable and the function
privateFunction() are accessed only by publicMethod() . Once an instance of MyObject is created,
there is no way to access privateVariable and privateFunction() directly; you can do so only by
way of publicMethod() .
You can define private and privileged members to hide data that should not be changed directly, as in
this example:
function Person(name){
this.getName = function(){
return name;
};
}
this.setName = function (value) {
name = value;
};
var person = new Person(“Nicholas”);
alert(person.getName()); //”Nicholas”
person.setName(“Greg”);
alert(person.getName()); //”Greg”
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