conga-annotations

Overview

This is a Node.js library which allows you to add annotations describing metdata data about constructors, methods, and properties within javascript files.

Example:

/**
 * @MyConstructorAnnotation("some value")
 */
function HelloWorld(){}

HelloWorld.prototype = {
    
    /**
     * @MyPropertyAnnotation(foo=[1,2,3,4], bar={"hello":"there"})
     */
    myProperty: 'foo',

    /**
     * @MyMethodAnnotation("foobar", something="hello")
     */
    myMethod: function(){

    }
}

Installation

> npm install conga-annotations

Usage

Create an Annotation

// my-constructor-annotation.js
// ----------------------------

var Annotation = require('conga-annotations').Annotation;

module.exports = Annotation.extend({

    /**
     * The name of the annotation

     * @type {String}
     */
    annotation: 'MyConstructorAnnotation',

    /**
     * The possible targets
     *
     * (Annotation.CONSTRUCTOR, Annotation.PROPERTY, Annotation.METHOD)
     *
     * @type {Array}
     */
    targets: [Annotation.CONSTRUCTOR],

    /**
     * The main value
     *
     * @type {String}
     */
    value: 'default value',

    /**
     * An additional attribute
     *
     * @type {String}
     */
    sample: 'default value for sample',
    
    /**
     * Optional initialization method that
     * can be used to transform data
     *
     * @param  {Object} data
     * @return {void}
     */
    init: function(data){
        // do something with data
    }
    
});

Add the Annotation to a File

// my-sample.js
// ------------

/**
 * @MyConstructorAnnotation("some value", sample="here is an attribute value")
 */
function MySample(){}

Parse the Annotation

// my-parser.js
// ------------

var path = require('path');
var annotations = require('conga-annotations');

// create the registry
var registry = new annotations.Registry();

// add annotations to the registry
registry.registerAnnotation(path.join(__dirname, 'my-constructor-annotation'));

// create the annotation reader
var reader = new annotations.Reader(registry);

// parse the annotations from a file
reader.parse(path.join(__dirname, 'my-sample.js'));

// get the annotations
var constructorAnnotations = reader.getConstructorAnnotations();
var methodAnnotations = reader.getMethodAnnotations();
var propertyAnnotations = reader.getPropertyAnnotations();

// loop through and handle the annotations
constructorAnnotations.forEach(function(annotation){

    // @MyConstructorAnnotation
    if (annotation.annotation === 'MyConstructorAnnotation'){

        // do something with the annotation data
        console.log(annotation.target); // -> "MySample"
        console.log(annotation.value); // -> "some value"
        console.log(annotation.sample); // -> "here is an attribute value"
    }

});

Supported Attribute Types

// string
@MyAnnotation(foo="a string")

// boolean
@MyAnnotation(foo=true)

// array
@MyAnnotation(foo=[1,2,3,4])

// object
@MyAnnotation(foo={hi:"there"})

// nested annotations
@MyAnnotation(foo=@MyNestedAnnotation("this is nested", foo=true))

// array of nested annotations
@MyAnnotation(foo=[@MyNestedAnnotation("nested 1"), @MyNestedAnnotation("nested 2")])

Working Example

http://code.runnable.com/VMlxhH4h9tNkarWi/conga-annotations-hello-world-example-for-node-js-and-congajs