Task Lists

Build Status

This is a community fork of GitHub's archived task_list gem.

- [x] Get
- [x] More
- [ ] Done
  • [x] Get
  • [x] More
  • [ ] Done


The Task List feature is made of several different components:

  • Markdown Ruby Filter
  • Summary Ruby Model: summarizes task list items
  • JavaScript: frontend task list update behavior
  • CSS: styles Markdown task list items

Usage & Integration

The backend components are designed for rendering the Task List item checkboxes, and the frontend components handle updating the Markdown source (embedded in the markup).

Backend: Markdown pipeline filter

Rendering Task List item checkboxes from source Markdown depends on the TaskList::Filter, designed to integrate with the html-pipeline gem. For example:

require 'html/pipeline'
require 'task_list/filter'

pipeline = HTML::Pipeline.new [

pipeline.call "- [ ] task list item"

Frontend: Markdown Updates

Task List updates on the frontend require specific HTML markup structure, and must be enabled with JavaScript.

Rendered HTML (the <ul> element below) should be contained in a js-task-list-container container element and include a sibling textarea.js-task-list-field element that is updated when checkboxes are changed.

- [ ] text
<div class="js-task-list-container">
  <ul class="task-list">
    <li class="task-list-item">
      <input type="checkbox" class="js-task-list-item-checkbox" disabled />
    <textarea class="js-task-list-field">- [ ] text</textarea>

Enable Task List updates with:

// Vanilla JS API
var container = document.querySelector('.js-task-list-container')
new TaskList(container)
// or jQuery API

NOTE: Updates are not persisted to the server automatically. Persistence is the responsibility of the integrating application, accomplished by hooking into the tasklist:change JavaScript event. For instance, we use AJAX to submit a hidden form on update.

Read through the documented behaviors and samples in the source for more detail, including documented events.


Task Lists are packaged as both a RubyGem with both backend and frontend behavior, and a Bower package with just the frontend behavior.

Backend: RubyGem

For the backend Ruby components, add this line to your application's Gemfile:

gem 'deckar01-task_list'

And then execute:

$ bundle

Frontend: NPM / Yarn

For the frontend components, add deckar01-task_list to your npm dependencies config.

This is the preferred method for including the frontend assets in your application.

Frontend: Bower

For the frontend components, add deckar01-task_list to your Bower dependencies config.

Frontend: Rails 3+ Railtie method

# config/application.rb
require 'task_list/railtie'

Frontend: Rails 2.3 Manual method

Wherever you have your Sprockets setup:

Sprockets::Environment.new(Rails.root) do |env|
  # Load TaskList assets
  require 'task_list/railtie'
  TaskList.asset_paths.each do |path|
    env.append_path path

If you're not using Sprockets, you're on your own but it's pretty straight forward. deckar01-task_list/railtie defines TaskList.asset_paths which you can use to manage building your asset bundles.


  • Ruby >= 2.1.0

At a high level, the Ruby components integrate with the html-pipeline library. The frontend components are vanilla JavaScript and include a thin jQuery wrapper that supports the original plugin interface. The frontend components are written in CoffeeScript and need to be preprocessed for production use.

A polyfill for custom events must be included to support IE10 and below.

Known issues

The markdown parser used on the front end produces false positives when looking for checkboxes in some complex nesting situations. To combat this issue, you can enable the sourcepos option in your markdown parser. This will avoid parsing the markdown on the front end, because the line numbers will be provided as attributes on the HTML elements. task_list checks for the source position attribute and falls back to manually parsing the markown when needed.


1.x to 2.x

The event interface no longer passes data directly to the callbacks arguments list. Instead the CustomEvent API is used, which adds data to the event.detail object.

// 1.x interface
el.on('tasklist:changed', function(event, index, checked) {
  console.log(index, checked)

// 2.x interface
el.on('tasklist:changed', function(event) {
  console.log(event.detail.index, event.detail.checked)

Testing and Development

JavaScript unit tests can be run with script/testsuite.

Ruby unit tests can be run with rake test.

Functional tests are useful for manual testing in the browser. To run, install the necessary components with script/bootstrap then run the server:

rackup -p 4011

Navigate to http://localhost:4011/test/functional/test_task_lists_behavior.html

Community Integration