The tiniest Markdown editor for the web

This project provides the simplest imaginable writing aid for Markdown-enabled <textarea> elements.

It only supports a handful of features, mostly to save you keystrokes. There's no GUI, no WYSIWYG features, and no preview.

It is also quite small at 2.5 KB minified & gzipped.

Check out the demo!

Installation

npm install --save mdarea

Or you can download the raw archive from the Releases section.

Add the mdarea.js or mdarea.min.js script to your page. You might need to use something like the keyboardevent-key-polyfill if you wish to support older browsers.

Since version 2.0 mdarea is written in TypeScript and therefore includes native typings out of the box. The package exposes the editor class as the default export and type declarations for the options object are available as named exports:

import MarkdownArea, { MarkdownAreaOptions } from 'mdarea';

Initialise your textareas like this:

<textarea id="mdarea"></textarea>

<script type="application/javascript">
    var editor = new MarkdownArea(document.getElementById('mdarea'));
</script>

API

• new MarkdownArea(element[, options])

  Creates a new editor instance for the given element. See below for the constructor options.

• editor.getElement()

  Returns the DOM element the editor instance is attached to.

• editor.setElement(element)

  Reattaches the editor instance to another textarea element.

• editor.getValue()

  Returns the current contents of the editor. Same as editor.getElement().value.

• editor.setValue(value)

  Sets the editor contents. Use this instead of editor.getElement().value = value, otherwise undo history will break!

• editor.destroy()

  Destroys the editor instance. This will unbind all event handlers and nullify all references to objects which might keep the editor in memory including the active textarea element. Remember to clear the reference to the editor instance that you kept until calling the destroy() method - the easiest way to do so is to call destroy() like this:

  editor = editor.destroy();

Constructor options

• indent (number | string, default: 4)

  How many spaces to use for indentation. If you specify a string, its length will be used - beware that the tab character has a length of 1!

• keyMap (object)

  Lets you customize the default key mapping of the editor. The keys of the object are action names, and the values are the key combinations as either comma-separated strings or arrays. See below for an explanation of the known actions and the default key combinations attached to them.

Key bindings

Shortcuts in the keyMap are specified as strings (or arrays thereof). Each shortcut is a combination of zero or more modifiers and a single key, separated by +. There are five supported modifiers: Ctrl, Shift, Alt, Meta and Cmd. The Cmd modifier represents the Cmd key on a Mac and the Ctrl key otherwise; the Ctrl modifier always means the Ctrl key and the Meta modifier always means the Windows / Cmd meta key. You'll probably always want to use the Cmd modifier in place of Ctrl or Meta. The key should be one of the known key values. Note that regular character keys a to z should be specified in lowercase, regardless of the presence or absence of the Shift modifier.

The four currently supported actions of the editor are:

• enter (default keys: Enter, Shift+Enter)

  This action takes care of smart Enter key handling. Invoked inside of a list item it will insert a new item at the current level, incrementing its number if applicable, or an indented newline within the current item if the Shift key is pressed. If invoked at the start of an empty list item it will remove the current item and place the cursor at the start of the line (exit the list, similarly to visual document editors). If invoked after an opening parenthesis an indented newline is inserted, similarly to common code editors.

• inline (default keys: ", ', `, *, _, [, ], (, ), {, }, <, >)

  This action inserts smart pairs of inline formatting characters. If the current selection is already surrounded by a formatting character and this action is invoked with the same character, the existing characters are removed (so selecting a word and pressing * will behave as "toggle bold").

• indent (default keys: Tab, Ctrl+m)

  This action indents the current line or the currently selected block of text. Note that the default key mapping for this action includes the Tab key, which will prevent navigation between form elements once the editor gains focus.

• outdent (default keys: Shift+Tab, Ctrl+Shift+m)

  This action performs the inverse of indent. The Shift+Tab default mapping will also similarly hamper form navigation.