Meteor could use Miro inside minimongo on the client, for example, and turn objects into vanilla JS before passing them to the app, if that implementation offered significant performance benefits (or equal or better performance and cleaner code, though the size of the Miro payload would also have to be weighed). Once the app has to deal with Miro objects, though, it starts to feel less like the JavaScript people know.
Meteor could use Miro inside minimongo on the client, for example, and turn objects into vanilla JS before passing them to the app, if that implementation offered significant performance benefits (or equal or better performance and cleaner code, though the size of the Miro payload would also have to be weighed). Once the app has to deal with Miro objects, though, it starts to feel less like the JavaScript people know.