Docco: Quick JavaScript Documentation

By  on  

Docco is a free Node.js-powered JavaScript documentation generation tool.  I was never big into documenting JavaScript methods within the source files themselves, but my team made the decision to go that route for a new project and I've come full swing.  Pair the in-source documentation with the Docco and you have pretty JavaScript documentation along side the source code.

You can install Docco using npm or grab the repo directly.  With Docco available, you can create code structures a la:

// The code in `oninstall` and `onactivate` force the service worker to
// control the clients ASAP.
self.oninstall = function(event) {

self.onactivate = function(event) {

// When fetching, distinguish if this is a resource fetch. If so,
// apply the server selection algorithm. Else, let the request reach the
// network. Could should be autoexplanatory.
self.onfetch = function(event) {
  var request = event.request;
  if (isResource(request)) {
  } else {

// A request is a resource request if it is a `GET` for something inside `imgs`.
function isResource(request) {
  return request.url.match(/\/imgs\/.*$/) && request.method === 'GET';

// Fetching from the best server consists of getting the server loads,
// selecting the server with lowest load, and compose a new request to
// find the resource in the selected server.
function fetchFromBestServer(request) {
  var session = request.url.match(/\?session=([^&]*)/)[1];
  return getServerLoads(session)
    .then(function(serverUrl) {
      // Get the resource path and combine with `serverUrl` to get
      // the resource URL but **in the selected server**.
      var resourcePath = request.url.match(/\/imgs\/[^?]*/)[0];
      var serverRequest = new Request(serverUrl + resourcePath);
      return fetch(serverRequest);

Running Docco on the contents above generates a nicely formatted page with "inline" comments on the left and comment-less code on the right:

Docco Sample

Docco has a few parameters for customization but the conversion is fairly simple and there are extension for gulp, grunt, and other utilities.  This type of doc generation and display is awesome for both teaching JavaScript and for maintenance amongst a team.  You can see Docco used within the Service Worker Cookbook code examples.

Recent Features

  • By
    6 Things You Didn’t Know About Firefox OS

    Firefox OS is all over the tech news and for good reason:  Mozilla's finally given web developers the platform that they need to create apps the way they've been creating them for years -- with CSS, HTML, and JavaScript.  Firefox OS has been rapidly improving...

  • By
    Create a CSS Cube

    CSS cubes really showcase what CSS has become over the years, evolving from simple color and dimension directives to a language capable of creating deep, creative visuals.  Add animation and you've got something really neat.  Unfortunately each CSS cube tutorial I've read is a bit...

Incredible Demos

  • By
    jQuery Countdown Plugin

    You've probably been to sites like RapidShare and MegaUpload that allow you to download files but make you wait a specified number of seconds before giving you the download link. I've created a similar script but my script allows you to animate the CSS font-size...

  • By
    JavaScript Battery API

    Mozilla Aurora 11 was recently released with a bevy of new features. One of those great new features is their initial implementation of the Battery Status API. This simple API provides you information about the battery's current charge level, its...


  1. Nibin

    Is there any workaround to support block comments in docco?

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!