Hey all, thanks for raising this issue!

Although I wasn’t here when this decision of CodeMirror over Monaco was made, I think I can understand some of the reasons and highlight them here:

• Mobile support: Monaco doesn’t have great mobile support, and this is crucial for Sandpack to deliver a uniform experience throughout all types of devices;
• Final bundle size: CodeMirror provides an easy way to load only the modules/extensions we want to, which gives us the possibility to lazy-loading and code-splitting the CodeEditor component. Meanwhile, Monaco is a heavy package, and that’s why CodeSandbox.io/CodeSandbox Embeds also defaults to CodeMirror in the mobile version (due to the previous reason too);
• Extensibility: TBH, I haven’t had many experiences with Monaco before, but I can tell what I’ve heard, and Monaco makes it hard to customize and extend some configuration - and Monaco provides a great API to extensions, which pretty much solved many of our problems;

Plus, Sandpack is designed to be extensible and provide a basic (but powerful) development experience, so the initial goal was never to support any language server by default but to provide ways (API, documentation, support) for the application consumer (you) implement it by yourself.

Typescript integration So what’s the point of the #237 discussion? We want to empower Sandpack users to use their favorite tools and working environment, but by doing it as an “extension” and not as a built-in solution. Similar to the approach we took with Prettier and Eslint, we would like to introduce more guides/recipes of how to do it by yourself and customize it in your favor, based on your needs.

Still want to use Monaco? In fact, you can easily switch from CodeMirror to Monaco at your end, as Sandpack exposes all the APIs needed to implement it. Here is an example using Monaco in Sandpack:

• Sandbox: https://codesandbox.io/s/sandpack-monaco-integration-citxd?file=/src/App.tsx
• Preview: https://citxd.csb.app/

Hope it makes clear this whole situation around the LSP and the editor options. Any further questions, I’m more than happy to answer them, otherwise, I’d close this issue. 😀

Thanks for the awesome responses with added context! 🙏 going to close this issue

If anyone else stumbles on this thread, found another good read on monaco vs codemirror technical blog post

• https://blog.replit.com/code-editors
• https://github.com/codesandbox/sandpack/discussions/237