Five ways to create objects…

1. Simple Object Literal

myApp.notepad  = {};
myApp.notepad.writeable = true;
myApp.notepad.font  = 'helvetica';
myApp.notepad.setFont = function(theFont) {
    myApp.notepad.font = theFont;
}

2. Nested Object Literal

myApp.notepad  = {
    writeable: true,
    font: 'helvetica',
    setFont: function(theFont) {
        this.font = theFont;
    }
}

3. Constructor using Object Literal

myApp.Notepad = function(defaultFont) {
    var  that = {};
    that.writeable = true;
    that.font = defaultFont;
    that.setFont = function(theFont) {
        that.font = theFont;
    }
    return that;
}

myApp.notepad1 =  myApp.Notepad('helvetica');

4. Simple Constructor for new

myApp.Notepad = function(defaultFont) {
    this.writeable = true;
    this.font = defaultFont;
    this.setFont = function(theFont) {
        this.font = theFont;
    }
}

myApp.notepad1  = new myApp.Notepad('helvetica');

5. Prototype with Constructor for new

myApp.Notepad = function(defaultFont) {
    this.font = defaultFont;
}
myApp.Notepad.prototype.writeable  = true;
myApp.Notepad.prototype.setFont  = function(theFont) {
    this.font = theFont;
}
myApp.notepad1  = new myApp.Notepad('helvetica');

The first two examples are best suited for creation of one-time objects. The last three describe templates for creation of multiple objects with a shared design.

All are useful. None are wrong. If I only needed one notebook in my app, I’d lean towards using Nested Object Literal since it neatly encapsulates all properties within its defining closures. For multiple notebook “instances” I like Prototype with Constructor for new simply because I can lock generic properties into the prototype object, making the constructor cleaner and more efficient

Next time I’ll talk about how to employ object inheritance with each methodology.

• JavaScript