Up to now, Raven has only supported running via Node.js. Node is primarily a JavaScript runtime: the underlying engine (V8) came from the Chrome web browser, but Node ditches the web pages and includes things like file system access, letting you use JS as a general-purpose language.
Like browsers, Node also supports WebAssembly, the virtual machine code that Raven compiles to. Say we have a file called main.rv which looks like this: