Object Oriented Programming

JavaScript supports object oriented programming through the Prototype pattern. To promote uniformity accross Nitro applications and middleware we promote the use of a couple of programming idioms.

Object Extension (Inheritance)

The standard Object.create mechanism is used as demonstrated in the following example:

var Content = function(title, body) {
}

Content.prototype.summary = function() {
    return this.body.splice(0, 10);
}    

var Article = function(title, body) {
    Content.call(this, title, body);
}

// Article inherits from Content.
Article.prototype = Object.create(Content.prototype);

var article = new Article("Hello", "Hello world");

Object Inclusion (Mixins)

It is obvious from the above example that only Single Inheritance is supported. To mitigate this shortcomming we can use Object Inclusion, ie Mixins. The concept will be demonstrated with an example:

var update = require("hash").Hash.update;

var Taggable = function(base) {
    update(base.prototype, Taggable.prototype);
}

Taggable.prototype.tags = function() {
    return this.tagString.split(",");
}

// Include Taggable functionality in Article.
Taggable.extend(Article);

var article = new Article("Hello", "Hello world");
article.tagString = "news,local";

print(article.tags());