In-browser rich document editor.
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Carbon is an extendable rich text editor in the browser that is consistent and beautiful. Carbon is inspired by Medium Editor. It is built on top of an internal model for an article that clients can translate to and from JSON and HTML.

The browser is built with extendability in mind and supports operations and history to allow proper undo-redo management with support for embeddable objects and uploading attachments.

Carbon is an open source project by your friends at Manshar - an open source publishing platform for Arabic content. Carbon supports both LTR and RTL languages.

Carbon is still in early alpha and you might run into bugs. If you do, please file a bug request or send a pull request with the proper fix. :mineral:

Compatibility And Tests

Carbon is still in alpha. Carbon is not yet compatible with all major browsers and platforms. Currently it only supports Desktop Browsers like Chrome, Firefox and Safari. We’re still working on adding more compatibility, especially on mobile browsers, feel free to send us pull requests 😄. We also don’t have a good unit tests coverage yet and we’ll continue working on adding those.


You can load Carbon from our CDN (Recommended)

<link href=""></script>
<script src=""></script>

To use the latest version use latest (Be careful this will most likey keep breaking until Carbon APIs are stable).

<link href=""></script>
<script src=""></script>

Or you can grab carbon source code (including minified files) using bower:

bower install carbon-tools/carbon

And then include the main Carbon scripts and css:

<link href="bower_components/carbon/dist/carbon.min.css"/>
<script src="bower_components/carbon/dist/carbon.min.js"></script>

After that you can create a new Carbon object and pass it the element you want to transfer into your editor.

<div id="my-editor"></div>
  var editor = new carbon.Editor(document.getElementById('my-editor'));

That’s it. You now have Carbon enabled. See demo/index.html source code and demo/rtl-demo.html for more usage examples.

carbon.Editor accepts a second optional parameters you can use to configure the editor with. Here’s a table of the parameters you can pass with their explanation:

Parameter Explanation Values
modules A list of custom components and extensions you’d like to enable in the editor.

The editor has built in extensions and components enabled for every editor, these include: [Section, Paragraph, List, Figure, FormattingExtension, ToolbeltExtension, UploadExtension]

A list of classes for each module you want to enable.

Default: []

Example: [YouTubeComponent, VimeoComponent]

rtl Whether this editor is an RTL editor or not. Boolean

Default: false

article A carbon.Article object to initiate the editor with. carbon.Article object.

Default: A carbon.Article instance with one Paragraph with placeholder ‘Editor’

The editor also exposes methods to allow the clients to interact with it.

Method Args Explanation
registerRegex regexStr: A regex string to listen to.

callback: A callback function to call when the regex is matched.

Registers a regex with the editor.
getHTML Returns HTML string represents the whole article
getJSONModel Returns JSON model for the article
loadJSON classmethod json: JSON model to create article model from Creates and sets a new article model from JSON format
install module: The module to install in the editor.
getModule name: Name of the module to return Returns the module with the given name
registerToolbar name: Toolbar name toolbar: The toolbar object to register Registers a toolbar with the editor
getToolbar name: Name of the toolbar to return Returns toolbar with the given name
addEventListener name: Event name handler: Callback handler for the event
registerShortcut shortcutId: A String representing the shortcut (e.g. "cmd+alt+1") handler: A function to call when the shortcut is triggered optForce: Optional argument whether to override an already registered shortcut Registers a shortcut listener with the editor
isEmpty Returns true if the editor is empty
getTitle Returns the first header paragraph text in the editor
getSnippet Returns the first non-header paragraph text in the editor

Installing More Modules

The editor by default installs:

  • Section, Paragraph, List and Figure Components

  • Formatting, Toolbelt and Upload Extensions

Carbon also package one other components that are not installed by default, you can install them by providing them to the modules attribute of the editor params, or by calling editor.install(module) method.


Article Model

The editor relies on carbon.Article to render and control the model. Article is made of Sections. A section is made of Components. A component can be a Paragraph, Figure, List or others that inherit from carbon.Component.


Component is an abstract construct that all components in the editor extend and inherits from. All components have these attributes and are setup by passing them as an object parameter to the constructor.

Parameter Explanation Values
name A unique name of the component instance. String

Default: Randomly generated unique ID using Utils.getUID()

editor A reference to the editor that contains this component instance. Editor instance
section A reference to the section that contains this component instance Section instance
inline Whether this component is a single line component If set to True in a paragraph, the editor will not allow the component to create more siblings.

Default: False

parentComponent If the component is nested and initialized in another component this points to the parent component

Each component will also inherit Component methods. Components are responsible of overriding and implementing some of these methods.

Method Explanation Should Override?
getNextComponent Returns the next component No
getPreviousComponent Returns the previous component No
getIndexInSection Returns the index of the component in its section No
getJSONModel Returns a JSON representation of the component. This representation must have at least a ‘component’ and ‘name’ attributes with component being the CLASS_NAME of the component and the unique name of the component instance. Must Override
getDeleteOps Returns the operations needed to delete this component Must Override
getInsertOps Returns the operations needed to be executed to insert this component in the editor Must Override
getLength Returns the length of the component content. For text components this is the text length and for other components this should be 1. Optional Override
getInsertCharsOps Returns operations needed to insert characters in a component (only needed for text-based components) Optional Override
getRemoveCharsOps Returns operations needed to remove characters in a component (only needed for text-based components) Optional Override
getUpdateOps Returns operations needed to update component’s attributes. Optional Override

Every component must also:

  • Expose a dom property that is the container element of the component. The dom element must set a name attribute equals to the property

  • Define a class variable CLASS_NAME with a string name for its class, usually matching its constructor name.

  • Register its constructor with the carbon.Loader module. This needs to happen at the load time

carbon.Loader.register(Compnent.CLASS_NAME, Component);
  • Implement an onInstall(editor) class method that is called when a component is installed in an editor.

  • Implement a fromJSON class method that allows the component to be recreated from its JSON representation.

  • Optionally worry about its selection and how users interact with it


Article consists of sections. Article is also responsible of transaction operations on the article and keeping history of the changes to allow undo and redo operations.


Section consists of components and is responsible of inserting and removing components in the section.


A paragraph takes few arguments when initializing it programmatically. Paragraph is any text-element that allow users to input text.

Parameter Explanation Values
text Text in this paragraph. String
placeholderText A placeholder text to show in the paragraph when it’s empty.
paragraphType The type of paragraph. Paragraph.Types = { Paragraph: 'p', MainHeader: 'h1', SecondaryHeader: 'h2', ThirdHeader: 'h3', Quote: 'blockquote', Code: 'pre', Caption: 'figcaption', ListItem: 'li' };

Default: Paragraph.Types.Paragraph

formats A list of objects representing formatting of the paragraph.

This attribute is mostly managed by the FormattingExtension.

Example: [{from: 3, to: 10, type: ‘em’}]


Figure component registers a regex to match any image links pasted in a new paragraph and replaces the link with an image. Figure component also handles its own selection by adding a click listener on the image.

Parameter Explanation Values
src The source attribute for the image inside the figure. Data URI, Remote absolute or relative URL
caption The caption text for the figure.

Internally the caption is implemented by nesting a Paragraph component with inline:true and placeholder:params.captionPlaceholder

captionPlaceholder Placeholder for the caption.
width Width of the figure in the editor. String

Default: ‘100%’


Parameter Explanation Values
tagName The tag name to use for the container of the component. Values: ‘ol’ (List.ORDERED_LIST_TAG) or ‘ul’ (List.UNORDERED_LIST_TAG)


components List of paragraphs components of type ListItem representing list items. Default: A list with a single empty Paragraph of type listItem.


Attachment is a class to track the progress of an upload in progress and update the inserted component attributes after it is done.

UploadExtension creates attachments when the user upload images and insert a pending figures into the editor by reading the image as data URL. The client is notified through an event and should handle persisting the file remotely. After the client is done persisting the file, they need to update the attachment attributes - e.g. Update the source to a remote URL.

Attachment has the following attributes.

Parameter Explanation
file The file the user choose in the file picker
figure Figure object tied to this file upload to update its attributes
insertedOps Operations used to insert the figure object. This allows attachment to update the history of insertedOps to match the new attributes to avoid any discrepancies.

And the following method can be used to update the attributes of the attachment.

Method Args Explanation
setAttributes attrs: An object with the attributes and their value to update to. Update attachment attributes

Editor Shortcuts

The editor supports formatting shortcuts:

  • Ctrl/Cmd+B to bold

  • Ctrl/Cmd+i to Italic

  • Ctrl/Cmd+u to Underscore

  • Ctrl/Cmd+s to Strikethrough

  • Ctrl/Cmd+k to Activate link field to type a URL and hit enter to apply it

  • Ctrl/Cmd+Alt+1/2/3 to apply header format (h1, h2, h3)

  • Ctrl/Cmd+Alt+4 to apply Quote

  • Ctrl/Cmd+Alt+5 to apply Code

Styling Carbon Editor

Carbon includes a default styling for the editor components and the toolbars. You can override these in your own stylesheet or not include the main stylesheet for carbon and build your own.

Extending Carbon Editor

There are currently two ways to extend the editor: Custom Components and Extensions. The difference is in the definition.

Custom Components are built to create multiple instances of and insert into the editor - e.g. YouTubeComponent allows people to insert multiple YouTube videos by creating multiple YouTubeComponent’s.

Whereas Extensions are meant to be initialized once and add functionality to the editor. For example, FormattingExtension enables formatting toolbars in the editor to allow formatting paragraphs and text.

Custom Components

Developers can write custom components to extend the editor with, currently there are two ways your component can interface with the editor and allow insertion: RegEx Triggers and Toolbelt.

RegEx Triggers

A custom component can register a regex to listen to with the editor. When that RegEx is matched when the user hits enter on the current paragraph the editor will notify the component that matched that regex. For example, YouTubeComponent registers a RegEx to match a YouTube link typed in a new paragraph and then replaces that paragraph with a YouTubeComponent which embeds the YouTube video in the editor!

See YouTubeComponent and GiphySearch to learn more about extending the editor.

Editor Toolbelt

A component (or an extension) can also add a button on the editor toolbelt to allow insertion into the editor. For example, YouTubeComponent could add a "Embed YouTube" Button to the toolbelt that prompts the user to paste a link URL.

See UploadExtension to see how you can add your own actions to the Toolbelt.


An extension is used to enable new global functionality to the editor. For example, UploadExtension adds an "Upload Image" button to the editor’s toolbelt which allows users to upload images and insert the image in the editor.

See ToolbeltExtension to see how you can extend the editor with extensions.

Serializing and Deserializing Article

You can store and load the article model you can serialize and deserialize the article to and from JSON format using editor.getJSONModel() and editor.loadJSON(json). For example, the following example saves the article in localStorage and loads it back.

var saveBtn = document.getElementById('saveBtn');
saveBtn.addEventListener('click', function() {
  var json = editor.getJSONModel();
  localStorage.setItem('article', JSON.stringify(json));
var loadBtn = document.getElementById('loadBtn');
loadBtn.addEventListener('click', function() {
  var jsonStr = localStorage.getItem('article');

See demo/index.html for an example of storing and loading from the localStorage.

Editor Events


Fired when the editor content changes.


Fired after an attachment has been added to the editor to allow clients to upload the attachment and update the source. The client can access the attachment object from event.detail.attachment. See Attachment for more details. The following example listens to the event and update the attachment source and caption after uploading to a remote resource.

editor.addEventListener('attachment-added', function(event) {
  var attachment = event.detail.attachment;
  ajax.uploadFile(attachment.file, function uploadComplete(data) {
      src: data.src,
      caption: data.caption


Fires when the selection in the editor changes.


We'll check out your contribution if you:

  • Provide a comprehensive suite of tests for your fork.
  • Have a clear and documented rationale for your changes.
  • Package these up in a pull request (all squashed and neat if possible).

We'll do our best to help you out with any contribution issues you may have.

Feel free to send pull requests implementing new components.


# clone
git clone --recursive git://

cd carbon
npm install
bower install

# start coding with live reloading
grunt serve

Run grunt test to run the tests and run grunt serve to build the project and open the demo page. Any changes will be built and you'd need to refresh the demo to see them. You can also run grunt to just build and watch files, you can use this when you want to write some tests and see them running as you change files.


Simplified BSD. See LICENSE in this directory.