zum/lib/topic.js

Zum is a simple event bus for NodeJS microservices using amp.

'use strict';

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

module.exports = () => {
  const queue = [];
  const socks = new Set();

  let n = 0;
  const queueing = false;

  const send = (buf, force) => {
    const sock = [...socks][n++ % socks.size];
    if (sock && sock.writable && !queueing || force && queueing) {
      sock.write(buf);
    } else {
      queue.push(['send', buf]);
    }
  };

  const broadcast = (buf, force) => {
    if (socks.size && !queueing || force && queueing) {
      for (const s of socks) s && s.writable && s.write(buf);
    } else {
      queue.push(['broadcast', buf]);
    }
  };

  const runners = { send, broadcast };
  const add = sock => socks.add(sock);
  const remove = sock => socks.delete(sock);

  return _extends({}, runners, { add, remove });
};