The monaco-editor npm package provides the code editor that powers VS Code, offering rich IntelliSense, validation for a variety of languages, and advanced editing features. It can be integrated into web applications to provide a full-fledged code editing experience.

What are monaco-editor's main functionalities?

Syntax highlighting and IntelliSense

This code initializes the Monaco Editor with JavaScript syntax highlighting and IntelliSense support.

var editor = monaco.editor.create(document.getElementById('container'), {
  value: 'function x() {\n  console.log("Hello world!");\n}',
  language: 'javascript'
});

Code validation and linting

This code adds a marker to the editor model, indicating an error at the specified position with a message.

monaco.editor.setModelMarkers(editor.getModel(), 'owner', [
  { startLineNumber: 1, startColumn: 1, endLineNumber: 1, endColumn: 1, message: 'Error message', severity: monaco.MarkerSeverity.Error }
]);

Custom themes

This code defines a custom theme for the editor and applies it.

monaco.editor.defineTheme('myTheme', {
  base: 'vs',
  inherit: true,
  rules: [{ background: 'EDF9FA' }],
  colors: { 'editor.foreground': '#000000' }
});
monaco.editor.setTheme('myTheme');

Keybindings and editor actions

This code adds a custom action to the editor that can be triggered with a keyboard shortcut.

editor.addAction({
  id: 'my-unique-id',
  label: 'My Label',
  keybindings: [monaco.KeyMod.CtrlCmd | monaco.KeyCode.KEY_S],
  run: function(ed) {
    alert('Action triggered!');
  }
});

Other packages similar to monaco-editor

Monaco Editor

Demo page

The Monaco Editor is the code editor that powers VS Code, a good page describing the code editor's features is here.

Try it out

See the editor in action here.

Learn how to extend the editor and try out your own customizations in the playground.

Browse the latest editor API at monaco.d.ts.

Issues

Please mention the version of the editor when creating issues and the browser you're having trouble in. Create issues in this repository.

Known issues

In IE, the editor must be completely surrounded in the body element, otherwise the hit testing we do for mouse operations does not work. You can inspect this using F12 and clicking on the body element and confirm that visually it surrounds the editor.

Installing

npm install monaco-editor

You will get:

inside dev: bundled, not minified
inside min: bundled, and minified
inside min-maps: source maps for min
monaco.d.ts: this specifies the API of the editor (this is what is actually versioned, everything else is considered private and might break with any release).

It is recommended to develop against the dev version, and in production to use the min version.

Integrate

Here is the most basic HTML page that embeds the editor. More samples are available at monaco-editor-samples.

<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="X-UA-Compatible" content="IE=edge" />
	<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
</head>
<body>

<div id="container" style="width:800px;height:600px;border:1px solid grey"></div>

<script src="monaco-editor/min/vs/loader.js"></script>
<script>
	require.config({ paths: { 'vs': 'monaco-editor/min/vs' }});
	require(['vs/editor/editor.main'], function() {
		var editor = monaco.editor.create(document.getElementById('container'), {
			value: [
				'function x() {',
				'\tconsole.log("Hello world!");',
				'}'
			].join('\n'),
			language: 'javascript'
		});
	});
</script>
</body>
</html>

Integrate cross domain

If you are hosting your .js on a different domain (e.g. on a CDN) than the HTML, you should know that the Monaco Editor creates web workers for smart language features. Cross-domain web workers are not allowed, but here is how you can proxy their loading and get them to work:

<!--
	Assuming the HTML lives on www.mydomain.com and that the editor is hosted on www.mycdn.com
-->
<script type="text/javascript" src="http://www.mycdn.com/monaco-editor/min/vs/loader.js"></script>
<script>
	require.config({ paths: { 'vs': 'http://www.mycdn.com/monaco-editor/min/vs' }});

	// Before loading vs/editor/editor.main, define a global MonacoEnvironment that overwrites
	// the default worker url location (used when creating WebWorkers). The problem here is that
	// HTML5 does not allow cross-domain web workers, so we need to proxy the instantion of
	// a web worker through a same-domain script
	window.MonacoEnvironment = {
		getWorkerUrl: function(workerId, label) {
			return 'monaco-editor-worker-loader-proxy.js';
		}
	};

	require(["vs/editor/editor.main"], function () {
		// ...
	});
</script>

<!--
	Create http://www.mydomain.com/monaco-editor-worker-loader-proxy.js with the following content:
		self.MonacoEnvironment = {
			baseUrl: 'http://www.mycdn.com/monaco-editor/min/'
		};
		importScripts('www.mycdn.com/monaco-editor/min/vs/base/worker/workerMain.js');
	That's it. You're good to go! :)
-->

More documentation

Find full HTML samples here.

Create a Monarch tokenizer here.

FAQ

❓ What is the relationship between VS Code and the Monaco Editor?

The Monaco Editor is generated straight from VS Code's sources with some shims around services the code needs to make it run in a web browser outside of its home.

❓ What is the relationship between VS Code's version and the Monaco Editor's version?

None. The Monaco Editor is a library and it reflects directly the source code.

❓ I've written an extension for VS Code, will it work on the Monaco Editor in a browser?

No.

❓ Why all these web workers and why should I care?

Language services create web workers to compute heavy stuff outside the UI thread. They cost hardly anything in terms of resource overhead and you shouldn't worry too much about them, as long as you get them to work (see above the cross-domain case).

❓ What is this loader.js? Can I use require.js?

It is an AMD loader that we use in VS Code. Yes.

❓ I see the warning "Could not create web worker". What should I do?

HTML5 does not allow pages loaded on file:// to create web workers. Please load the editor with a web server on http:// or https:// schemes. Please also see the cross domain case above.

❓ Is the editor supported in mobile browsers or mobile web app frameworks?

No.

❓ Why doesn't the editor support TextMate grammars?

all the regular expressions in TM grammars are based on oniguruma, a regular expression library written in C.
the only way to interpret the grammars and get anywhere near original fidelity is to use the exact same regular expression library (with its custom syntax constructs)
in VSCode, our runtime is node.js and we can use a node native module that exposes the library to JavaScript
in Monaco, we are constrained to a browser environment where we cannot do anything similar
we have experimented with Emscripten to compile the C library to asm.js, but performance was very poor even in Firefox (10x slower) and extremely poor in Chrome (100x slower).
we can revisit this once WebAssembly gets traction in the major browsers, but we will still need to consider the browser matrix we support. i.e. if we support IE11 and only Edge will add WebAssembly support, what will the experience be in IE11, etc.

Development setup

Please see CONTRIBUTING

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

License

MIT

[0.8.0] (18.01.2017)

This release has been brewing for a while and comes with quite a number of important changes.
There are many bugfixes and speed/memory usage improvements.
Now shipping TypeScript v2.1.5 in monaco-typescript (JS and TS language support).

No longer supporting IE9 and IE10

we have not made the editor fail on purpose in these browsers, but we have removed IE9/IE10 targeted workarounds from our codebase;
now using Typed Arrays in a number of key places resulting in considerable speed boosts and lower memory consumption.

Monarch Tokenizer

Monarch states are now memoized up to a depth of 5. This results in considerable memory improvements for files with many lines.
Speed improvements to Monarch tokenizer that resulted in one breaking change:
when entering an embedded mode (i.e. nextEmbedded), the state ending up in must immediately contain a nextEmbedded: "@pop" rule. This helps in quickly figuring out where the embedded mode should be left. The editor will throw an error if the Monarch grammar does not respect this condition.

Tokens are styled in JS (not in CSS anymore)

This is a breaking change
Before, token types would be rendered on the span node of text, and CSS rules would match token types and assign styling to them (i.e. color, boldness, etc.to style tokens)
To enable us to build something like a minimap, we need to know the text color in JavaScript, and we have therefore moved the token style matching all to JavaScript. In the future, we foresee that even decorations will have to define their color in JavaScript.
It is possible to create a custom theme via a new API method monaco.editor.defineTheme() and the playground contains a sample showing how that works.
Token types can be inspected via F1 > Developer: Inspect tokens. This will bring up a widget showing the token type and the applied styles.

API changes:

Namespaces

added monaco.editor.onDidCreateEditor that will be fired whenever an editor is created (will fire even for a diff editor, with the two editors that a diff editor consists of).
added monaco.editor.tokenize that returns logical tokens (before theme matching, as opposed to monaco.editor.colorize).
added monaco.languages.registerTypeDefinitionProvider

Models

removed IModel.getMode().
structural changes in the events IModelLanguageChangedEvent, IModelDecorationsChangedEvent and IModelTokensChangedEvent;
changed IModel.findMatches, IModel.findNextMatch and IModel.findPreviousMatch to be able to capture matches while searching.

Editors

ICodeEditor.addAction and IDiffEditor.addAction now return an IDisposable to be able to remove a previously added action.
renamed ICodeEditor.onDidChangeModelMode to ICodeEditor.onDidChangeModelLanguage;
ICodeEditor.executeEdits can now take resulting selection for better undo/redo stack management;
added ICodeEditor.getTargetAtClientPoint(clientX, clientY) to be able to do hit testing.
added IViewZone.marginDomNode to be able to insert a dom node in the margin side of a view zone.
settings:
- lineDecorationsWidth can now take a value in the form of "1.2ch" besides the previous accepted number (in px)
- renderLineHighlight can now take a value in the set 'none' | 'gutter' | 'line' | 'all'.
- added fixedOverflowWidgets to render overflowing content widgets as 'fixed' (defaults to false)
- added acceptSuggestionOnCommitCharacter to accept suggestions on provider defined characters (defaults to true)
- added emptySelectionClipboard - copying without a selection copies the current line (defaults to true)
- added suggestFontSize - the font size for the suggest widget
- added suggestLineHeight - the line height for the suggest widget
diff editor settings:
- added renderIndicators - Render +/- indicators for added/deleted changes. (defaults to true)

Thank you

Nico Tonozzi (@nicot): Register React file extensions PR monaco-typescript#12
Jeong Woo Chang (@inspiredjw): Cannot read property 'uri' of null fix PR vscode#13263
Jan Pilzer(@Hirse): Add YAML samples PR monaco-editor#242

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Package last updated on 18 Jan 2017

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monaco-editor