@fanoutio/eventstream/build/stream/AddressedEventsReadable.js

Connect-compatible middleware that enables the easy creation of EventStream endpoints

import { Readable } from 'stream';
import Debug from 'debug';
const debug = Debug('eventstream');
export default class AddressedEventsReadable extends Readable {
    addressedEvents;
    channels;
    listenHandle;
    constructor(addressedEvents, channels) {
        super({
            objectMode: true,
        });
        this.addressedEvents = addressedEvents;
        debug('AddressedEventsReadable constructed with channels', channels);
        this.channels = channels;
        this.listenHandle = null;
    }
    _read(_size) {
        debug('AddressedEventsReadable _read');
        if (this.listenHandle == null) {
            debug('AddressedEventsReadable setting up listener');
            this.listenHandle = this.addressedEvents.addListener((addressedEvent) => {
                if (this.channels.includes(addressedEvent.channel)) {
                    this.push(addressedEvent.event);
                }
            });
        }
    }
    _destroy(error, callback) {
        debug('AddressedEventsReadable _destroy');
        if (this.listenHandle != null) {
            this.listenHandle();
            this.listenHandle = null;
        }
        super._destroy(error, callback);
    }
}