Using prototype to define a getter/setter

Question

If I have an application with a bunch of getters and setters, then I think that I need to use closures to keep the value of the setter, don't I?

Here's what I've got so far, but I think these two methods should be returning functions (closures). I don't think I should be using this.local.result because the two will conflict.

myApplication = function(){
    this.local = {};  
};
myApplication.prototype.myFirstMethod = function(){
    if (arguments.length) {
        this.local.result = arguments[0];
    } else {
        return this.local.result;
    } 
};
myApplication.prototype.mySecondMethod = function(){
    if (arguments.length) {
        this.local.result = arguments[0];
    } else {
        return this.local.result;
    } 
};

var app = new myApplication();
app.myFirstMethod(1);
result = app.myFirstMethod();

console.log(result);

Answer 1

The purpose of using closures is to keep the variable private (not directly accessible from the global scope).

Here is how to use a closure:

myApplication.prototype.myFirstMethod = (function () {
    var data = '';
    return function () {
        if (arguments.length) {
            data = arguments[0];
        } else {
            return data;
        }
    }
})();

If you dont need the data to be private, you can simply do this:

myApplication.prototype.myFirstMethod = function(){
    if (arguments.length) {
        this.local['firstData'] = arguments[0];
    } else {
        return this.local['firstData'];
    } 
};