Communication from webcontainer to host

[paoloricciuti]

I was trying to make the svelte inspector work in svelte lab...I kinda did it but it's a bit ugly because I have to read from the terminal. I saw that in the web container there's a custom code binary that stack blitz uses to open the tab. How does it work? Is there some even I can listen on? In general, there's a way to communicate from the web container to the page mounting it without using the terminal?

[Nemikolh]

Hey @paoloricciuti! 👋 Thanks for asking!

There's an event that is not yet exposed but that the code binary uses under the hood to communicate that a file should be "opened" (the embedder decides what to do with that information) at a specific line.

It's basically another event type that we should expose via webcontainerInstance.on(<event>, listener).

I'll mention this to the team because I've come across this in TutorialKit too and I think this is really easy to add.

[paoloricciuti]

Great...it would be cool to have a generic way to communicate to and from the web container.

[Nemikolh]

I agree, we've talked about adding a MessagePort that could be obtained like nodejs' parentPort but it's not as easy short term. And there's a lot of debate on how it would work with regards to child processes and the event loop.

Would having that extra 'code' event be enough for you for now?

[paoloricciuti]

Would having that extra 'code' event be enough for you for now?

Oh yeah absolutely...I just think that in general communication in and out the web container should be addressed (just making a proposal obviously, not pretending 😁)