Thanks for joining the webinar! I’ll respond to your question below. Since this message may also be read by people who haven’t seen the webinar, I’ll include some context here which might be redundant for you - please bear with me.
First of all, I’d like to clarify that Axon’s subscription queries have absolutely nothing to do with Vaadin. The key reason for using Vaadin in demos is that it allows me to create and adapt front-ends extremely quickly, fully in Java. (I’m not a skilled front-end dev at all.) Most real-life Axon projects use different front-end technology of course.
Axon’s subscription queries are based on Reactor. The result of a subscription query consists of two things: a Mono with the initial result and a Flux with the updates. From that point on, it’s up to you as a developer what to do with this.
If you want to get your updates to an Angular/React/Vue based front-end, Spring 5 will make your life pretty easy. A RestController can simply return the Flux. I’ve added some code to the repository to include a restcontroller like this. For an example on how to combine that with Angular, you might have a look here. If you want to work this out to a complete example, I’ll happily accept a pull request on the repo