Provide Kotlin JS Library For vertx-sockjs-service-proxy

[napperley]

Vert.x provides Sock JS Service Proxy libraries (for Java, Kotlin JVM, JS etc) however there isn't one available for Kotlin JS (video). Kotlin covers both server-side (using Kotlin JVM or Kotlin JS) and web front-end (Kotlin JS only at the moment) development, which means it can be used to develop full stack web apps (Thinkter sample, Kotlin Conf app). By providing a Kotlin JS library it enables a Kotlin JS app (web front-end) to easily communicate with a Vert.x app (server-side) through asynchronous message passing via Web Sockets, which should in theory be type safe with straightforward interop.

In order to have the Kotlin JS lib developed the following is needed:

• Access to the Vert.x Sock JS Service Proxy lib source code
• Reference documentation for Vert.x Sock JS Service Proxy lib
• Type information on Vert.x Sock JS Service Proxy lib APIs

If the Kotlin JS lib is going to be developed then it would be highly advisable to structure the lib as part of a Kotlin multi-platform project (video). Kotlin Native (overview video, Kotlin Conf 2017 video) which is under development has experimental WASM support (refer to the HTML 5 Canvas sample), which allows the technology to be used as an alternative for web front-end development. Most major web browsers (incl the mobile ones) officially support WASM.