JSClassFinder

A tool to detect class-like structures in legacy JavaScript code (i.e., prior to ECMAScript 6).

Example of Class detected by JSClassFinder

function Circle (radius) { //  class
   this.radius= radius; // attribute
   this.getArea= function () { // method
     return (3.14 * this.radius * this.radius);
   }
 }
 
 var myCircle = new Circle (10); // Circle instance
 
 function Circle2D (x, y) { // class Circle2D
   this.x = x;
   this.y= y;
 }

// Circle2D is a subclass of Circle
Circle2D.prototype = new Circle(10);

// Circle2D extends Circle with new methods
Circle2D.prototype.getX = function () {
  return (x);
}
Circle2D.prototype.getY = function () {
  return (y);
}

Example of Class Diagram Generated by JSClassFinder (for algorithm.js)

Data about Class Emulation in 60 JavaScript systems

Installation

JSClassFinder is implemented in Pharo (a Smalltalk-like language)
You can download a ready-to-use Pharo image here, or use the instructions below to install JSClassFinder inside your own Pharo image:
1 – Open Monticello browser
2 – Add a new repository (+Repository) of type HTTP
3 – Fill in the required information as below
 MCHttpRepository
    location: 'http://smalltalkhub.com/mc/LeonardoHumberto/JSClasses/main'
    user: ''
    password: ''
4 – Choose the newest release

Input

JSClassFinder expects the AST of a JS source code, in JSON format, as input.
To generate the AST we use Esprima.
Use the instructions below to use Esprima under Node.js:
1- install Node.js
2- load Esprima package : “npm install esprima”
3- Ok, you are ready to execute Esprima commands.

The file analyse.js is one example of script that can be used to generate JSON files.

More Info

Download

Ready-to-use Pharo image with JSClassFinder installed
JSClassFinder packages on SmalltalkHub
Dataset for SANER paper