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

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

import { Writable } from 'stream';
import Debug from 'debug';
const debug = Debug('eventstream');
export default class ChannelWritable extends Writable {
    channelPublisher;
    constructor(channelPublisher) {
        super({
            objectMode: true,
        });
        this.channelPublisher = channelPublisher;
    }
    async _write(event, _encoding, callback) {
        let err;
        try {
            debug('ChannelWritable.write');
            await this.channelPublisher.publishEvent(event);
        }
        catch (ex) {
            err = ex instanceof Error ? ex : new Error(String(ex));
        }
        // The above is an async method that doesn't return until the publish has finished
        // (if GRIP is enabled then it won't return until GRIP publish has finished)
        // For this reason this should apply backpressure to the writing.
        if (err != null) {
            callback(err);
        }
        else {
            callback();
        }
    }
}