Hydro/hydro/service/bus.js

const EventEmitter = require('events').EventEmitter;
const bus = new EventEmitter();
module.exports = {
    subscribe(events, handler) {
        for (let event of events)
            bus.on(event, handler);
    },
    unsubscribe(events, handler) {
        for (let event of events)
            bus.off(event, handler);
    },
    publish(event, data) {
        bus.emit(event, { value: data, event });
    }
};