codemirror.dart

What is it?

A Dart wrapper around the CodeMirror text editor. From codemirror.net:

CodeMirror is a versatile text editor implemented in JavaScript for the browser. It is specialized for editing code, and comes with a number of language modes and addons that implement more advanced editing functionality.

Note: This is NOT a Flutter package, it is a Dart package for writing web applications like DartPad.

An example

final options = <String, String>{
  'mode': 'javascript',
  'theme': 'monokai'
};

final editor = CodeMirror.fromElement(
    document.querySelector('#textContainer')!, options: options);
editor.doc.setValue('foo.bar(1, 2, 3);');

See also our example/ directory.

How do I use it?

In your main html file, link to the style sheet:

<link href="/mirrors/codemirror.dart/tree/master/packages/codemirror/codemirror.css" rel="stylesheet">

reference the CodeMirror JavaScript code:

<script src="//mirrors/codemirror.dart/tree/master/packages/codemirror/codemirror.js"></script>

and, in your Dart code, import the library:

import 'package:codemirror/codemirror.dart';

What about modes? Addons?

This Dart package ships with several language modes built in. CodeMirror itself supports over 100 modes; the modes built into the Dart package include the usual suspects for web development - css, html, dart and javascript as well as a few others. In order to add additional modes, you’ll need to reference the mode file from your html entry point. So,

<script src="//mirrors/codemirror.dart/tree/master/packages/codemirror/mode/lua.js"></script>

will bring in support for Lua.

Similarly with addons, we’ve included a few common ones, and have made the others available to import on a case-by-case basis. In order to use the active-line addon, import:

<script src="//mirrors/codemirror.dart/tree/master/packages/codemirror/addon/selection/active-line.js"></script>

Be aware that many addons need additional configuration in order to enable then. This is generally done by passing values into the options of the CodeMirror constructor.

Some addons are exposed through the main Dart interface. Some are exposed via side-car Dart libraries available in the main package, and some have yet to be exposed. Pull requests welcome :)

Themes

By importing the codemirror.css file:

<link href="/mirrors/codemirror.dart/tree/master/packages/codemirror/codemirror.css" rel="stylesheet">

You get access to all the CodeMirror themes. If you only want a few, or don’t want to pay the network roundtrip cost to load all the themes, you can import only the ones you’re interested in:

<link href="/mirrors/codemirror.dart/tree/master/packages/codemirror/theme/monokai.css" rel="stylesheet">
<link href="/mirrors/codemirror.dart/tree/master/packages/codemirror/theme/zenburn.css" rel="stylesheet">

Disclaimer

This is not an official Google product.