Codemirror

The excellent CodeMirror editor as a React.js component.

Demo & Examples

Live demo: JedWatson.github.io/react-codemirror

To build the examples locally, run:

npm install
npm start

Then open localhost:8000 in a browser.

Installation

The easiest way to use codemirror is to install it from NPM and include it in your own React build process (using Browserify, Webpack, etc).

You can also use the standalone build by including dist/react-codemirror.js in your page. If you use this, make sure you have already included React, and it is available as a global variable.

npm install react-codemirror --save

Ensure that codemirror.css is loaded. It can be included in your module css as shown in example.less or linked explicitly in your index.html file e.g <link href="css/codemirror.css" rel="stylesheet">.

Usage

var React = require('react');
var Codemirror = require('react-codemirror');

var App = React.createClass({
	getInitialState: function() {
		return {
			code: "// Code"
		};
	},
	updateCode: function(newCode) {
		this.setState({
			code: newCode
		});
	},
	render: function() {
		var options = {
			lineNumbers: true
		};
		return <Codemirror value={this.state.code} onChange={this.updateCode} options={options} />
	}
});

React.render(<App />, document.getElementById('app'));

Methods

• focus focuses the CodeMirror instance
• getCodeMirror returns the CodeMirror instance, available .

You can interact with the CodeMirror instance using a ref and the getCodeMirror() method after the componentDidMount lifecycle event has fired (including inside the componentDidMount event in a parent Component).

Properties

• autoSave Boolean automatically persist changes to underlying textarea (default false)
• value String the editor value
• options Object (newValue) options passed to the CodeMirror instance
• onChange Function (newValue) called when a change is made
• onFocusChange Function (focused) called when the editor is focused or loses focus

See the CodeMirror API Docs for the available options.

Using Language Modes

Several language modes are included with CodeMirror for syntax highlighting.

By default (to optimise bundle size) all modes are not included. To enable syntax highlighting:

• install the codemirror package dependency (in addition to react-codemirror)
• require the language modes you wish to make available after you require react-codemirror itself
• set the mode option in the options object

var React = require('react');
var Codemirror = require('react-codemirror');
require('codemirror/mode/javascript/javascript');
require('codemirror/mode/xml/xml');
require('codemirror/mode/markdown/markdown');

<Codemirror ... options={{
	mode: 'javascript'
}} />

See the example source for a reference implementation including JavaScript and markdown syntax highlighting.

License

MIT. Copyright (c) 2016 Jed Watson.