Hack to load elm code into node.js. Requires path to Elm runtime file. Also included is an example file.

document-wrapper.js

var events = require('events');
var emitter = new events.EventEmitter();

function EventShim() {}

// String -> Boolean -> Boolean -> ()
EventShim.prototype.initEvent = function(t, bubbles, cancellable) {
	this.name = t;
	// Set by Elm.
	this.value = undefined;
}

module.exports = {
	// String -> Event
	createEvent: function(eventtype) {
		// eventtype should be "event", not enforced
		return new EventShim();
	}, 

	// Event -> ()
	dispatchEvent: function(e) {
		emitter.emit(e.name, e.value)
	},
	
	// String -> (Event -> ()) -> ()
	addEventListener: function(event, callback) {
		var wrapped = function(value) {
			callback({value: value});
		}
		emitter.on(event, wrapped);
	}
	
}

elmloader.js

var vm = require("vm");
var fs = require("fs");

var sandbox = { document: require('./document-wrapper.js') };

module.exports = function(runtimepath, modulepath) {
  var runtime = fs.readFileSync(runtimepath);
  var elmmodule = fs.readFileSync(modulepath);
  vm.runInNewContext(runtime, sandbox, runtimepath);
  vm.runInNewContext(elmmodule, sandbox, modulepath);

  return sandbox.Elm;
}

example.js

var elmloader = require("./elmloader.js")
var Elm = elmloader('elm-runtime.js', 'build/Main.js')

var w = Elm.worker(Elm.Squarer)
var send = w.send('input')

console.log("Attempting to send")

w.recv('reply', function(e) {console.log("Got", e.value)});

for (var k = 0; k < 10; k++)
	send(k);

Main.elm

module Squarer where

import JavaScript as JS

foreign import jsevent "input"
        (JS.fromInt 0)
        inputs: Signal JS.JSNumber

foreign export jsevent "reply"
        outputs: Signal JS.JSNumber

numbers = JS.toInt <~ inputs
squares = (\n -> n^2) <~ numbers
outputs = JS.fromInt <~ squares