monaco-editor

What is monaco-editor?

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

ace

Ace is a standalone code editor written in JavaScript. It is similar to monaco-editor but with a different API and less out-of-the-box language support. Ace is lightweight and can be easier to integrate into existing projects.

codemirror

CodeMirror is another browser-based code editor with features like syntax highlighting, a rich API, and various language modes. It is less resource-intensive than monaco-editor and is often used in scenarios where performance is critical.

brace

Brace is a fork of Ace that packages the editor for use with browserify, which can make it easier to use with npm and Node.js-based build systems. It offers similar functionality to Ace.

README

Monaco Editor

The Monaco Editor is the code editor which powers VS Code, with the features better described here.

Please note that this repository contains no source code for the code editor, it only contains the scripts to package everything together and ship the monaco-editor npm module.

Try it out

Try the editor out on our website.

Installing

$ npm install monaco-editor

You will get:

• inside esm: ESM version of the editor (compatible with e.g. webpack)
• inside dev: AMD bundled, not minified
• inside min: AMD 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.

Documentation

• Learn how to integrate the editor with these complete samples.
  • Integrate the AMD version.
  • Integrate the AMD version cross-domain
  • Integrate the ESM version
• Learn how to use the editor API and try out your own customizations in the playground.
• Explore the API docs or read them straight from monaco.d.ts.
• Read this guide to ensure the editor is accessible to all your users!
• Create a Monarch tokenizer for a new programming language in the Monarch playground.
• Ask questions on StackOverflow! Search open and closed issues, there are a lot of tips in there!

Issues

Create issues in this repository for anything related to the Monaco Editor. Always mention the version of the editor when creating issues and the browser you're having trouble in. Please search for existing issues to avoid duplicates.

Known issues

In IE 11, the editor must be surrounded in the body element, otherwise the hit testing performed for mouse operations does not work. You can inspect this using F12 and click on the body element and confirm that visually it surrounds the editor.

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.

Note: If the extension is fully based on the LSP and if the language server is authored in JavaScript, then it would be possible.

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

Language services create web workers to compute heavy stuff outside of 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 [e-mail] with any additional questions or comments.

License

Licensed under the MIT License.

Changelog

[0.15.6] (23.11.2018)

• Fixes issue with context menu (https://github.com/Microsoft/monaco-editor/issues/1199)