CSP channels with ES6 generators, inspired by Clojurescript's core.async and Go


Communicating sequential processes for Javascript (like Clojurescript core.async, or Go).

var csp = require("js-csp");

Pingpong (ported from Go).

function* player(nametable) {
  while (true) {
    var ball = yield csp.take(table);
    if (ball === csp.CLOSED) {
      console.log(name + ": table's gone");
    ball.hits += 1;
    console.log(name + " " + ball.hits);
    yield csp.timeout(100);
    yield csp.put(table, ball);
csp.go(function* () {
  var table = csp.chan();
  csp.go(player, ["ping", table]);
  csp.go(player, ["pong", table]);
  yield csp.put(table, {hits: 0});
  yield csp.timeout(1000);

There are more under examples directory.

This is a very close port of Clojurescript's core.async. The most significant difference is that the IOC logic is encapsulated using generators (yield) instead of macros. Therefore resources on core.async or Go channels are also helpful.

js-csp requires ES6 generators.

Earlier versions of Firefox either had ES6 generators turned off, or supported only old style generators.

Run with --harmony or --harmony-generators flag. Check support using

node --v8-options | grep harmony

Turn on an experimental flag. Look for "Enable Experimental JavaScript" at chrome://flags.

Use one of the js-to-js compilers:

Or, if you use Python's Twisted: https://github.com/ubolonton/twisted-csp

Or, if you want a better language: https://github.com/clojure/core.async

It's available for both npm and bower. For browsers, use browserify+npm or browserify+bower+debowerify.

npm install js-csp
bower install js-csp
  • Multiplexing, mixing, publishing/subscribing.
  • Add more documentation and examples.
  • Add conversion functions that "de-IOC" promises and callback-based APIs (e.g. Web Workers).
  • Investigate error handling in goroutines:
    • Special yield waitFor that either returns a value or throws an error from the result channel.
    • Exception propagation & stack capturing.
  • Explore how deep yields (yield*) affect composability.
  • Deadlock detector.
  • Hands-on examples.
  • http://swannodette.github.io/2013/08/24/es6-generators-and-csp
  • https://github.com/clojure/core.async
  • https://github.com/olahol/node-csp

Distributed under MIT License.