Topological sort of directed acyclic graphs (like dependecy lists)


Sorting directed acyclic graphs, for Node.js and the browser This was originally done by Marcel Klehr. Why not checkout his original repo?

There are a few ways for installing Toposort. Here are them:

  • Via NPM: npm install toposort-class
  • Via Bower: bower install toposort
  • Via Git: git clone git://
  • Direct download for use in the browser

Let's say you have the following dependency graph:

  • Plugin depends on Backbone and jQuery UI Button;
  • Backbone depends on jQuery and Underscore;
  • jQuery UI Button depends on jQuery UI Core and jQuery UI Widget;
  • jQuery UI Widget and jQuery UI Core depend on jQuery;
  • jQuery and Underscore don't depend on anyone.

Now, how would you sort this in a way that each asset will be correctly placed? You'll probably need the following sorting:

  • jQuery, jQuery UI Core, jQuery UI Widget, jQuery UI Button, Underscore, Backbone, Plugin

You can achieve it with the following code, using toposort-class:

var Toposort = require('toposort-class'),
    t = new Toposort();
t.add("jquery-ui-core", "jquery")
 .add("jquery-ui-widget", "jquery")
 .add("jquery-ui-button", ["jquery-ui-core", "jquery-ui-widget"])
 .add("plugin", ["backbone", "jquery-ui-button"])
 .add("backbone", ["underscore", "jquery"]);
/* Will output:
 * ['jquery', 'jquery-ui-core', 'jquery-ui-widget', 'jquery-ui-button', 'underscore', 'backbone', 'plugin']
 * And you're done.

First of all:

var Toposort = require('toposort-class'),
    t = new Toposort();
// If you prefer, you can do this way also: 
= new require('toposort-class').Toposort();
  • {String} item - The name of the dependent item that is being added
  • {Array|String} deps - A dependency or list of dependencies of item

Returns: {Toposort} The Toposort instance, for chaining.

Returns: {Array} The list of dependencies topologically sorted.

This method will check for cyclic dependencies, like "A is dependent of A".

MIT License