Coming from Ruby, Elixir feels like a powerful, beautiful language with a surprisingly radical but ultimately simple approach to concurrency thanks to Erlang/BEAM, and Phoenix is like Rails 2006, as far as the framework to sell Elixir's advantages to the masses. It's very powerful and scaling "just works". All Elixir needs now is a viable ElixirScript that can compile down to JS/WASM, and along with Nerves it's ready for world domination. ;)

I'm not sure why you want to compile Elixir or Erlang to JS... Most of the magic of the language is provided by BEAM and OTP which for a multitude of reasons cannot be properly implemented in any JS engine/backend I'm aware of. If anything I'd think the abstractions of Elixir/Erlang would be cumbersome and very awkward when writing performant code which had to be transpiled to JS. The biggest reason being is BEAM can do preemptive scheduling, interrupting a running process to ensure all have equal execution time. This is a stark contrast to everything I know about how most any other VM or runtime work (which cannot preempt).

While yes the language is nice, I think using something like Opal would provide most of the syntactic pleasantries while being easier to understand when it comes to tuning and debugging.

If what I'm saying is nonsense, I'm missing the point, or short sighted please learn me! :)

btown

With the right abstractions and (adhered-to) guidelines, a library in a non-preemptive language can allow your code to effectively yield to the scheduler so often that you get many of the benefits of preemptiveness. React is moving in this direction with their ongoing Fiber project [0] - since components are encouraged to be granular, and must be loosely coupled, the new React scheduler can take well-structured React code and plan the rendering of various subtrees with high levels of control. In fact, there's a TON of similarities between React's component model and the BEAM actor model: a component's "mailbox" consists of inbound props, outbound async callbacks to the component that requested its instantiation, and outbound assertions that the component desires to communicate props to new instances of other components.

One could imagine a compiler that inserts a yield around the calculation done in each Elixir AST node, and/or one which allows first-class representation of React components as Elixir processes, complete with JSX-like syntax. Very interesting to think about.

[0] https://github.com/acdlite/react-fiber-architecture

EDIT: Should also add that the shared-nothing messaging model translates very well to the requirements for Web Worker interop, so you actually could get multithreading.