How to use nsqjs - 3 common examples

function consume(subject, channel, reply) {
    const readerKey = `${subject}.${channel}`

    // only one reader per topic channel combination
    if (readers.has(readerKey)) {
      return reply()
    }

    // if not exist, create Reader instance
    const reader = new Nsq.Reader(subject, channel, opts.nsqReader)

    reader.connect()

    reader.on(Nsq.Reader.NSQD_CONNECTED, (host, port) => {
      hemera.log.info('NSQ Reader connected to %s:%s', host, port)
      reply()
    })

    reader.on(Nsq.Reader.DISCARD, msg => {
      hemera.log.warn(msg, 'NSQ Message was discarded')
    })

    reader.on(Nsq.Reader.ERROR, err => {
      hemera.log.error(err, 'NSQ Reader error')
      reply(err)
      // Let it crash and restart

},
        err => {
          if (!err) {
            return msg.finish()
          }

          msg.requeue()
        }
      )
    })

    readers.set(readerKey, reader)
  }

  // only one writer for this service
  const writer = new Nsq.Writer(
    opts.nsqWriter.host,
    opts.nsqWriter.port,
    opts.nsqWriter.options
  )

  writer.connect()

  writer.on('error', err => {
    hemera.log.error(err, 'NSQ Writer error')
    hemera.fatal() // Let it crash and restart
  })

  writer.on('closed', () => {
    hemera.log.warn('NSQ Writer closed')
  })

OutputNsq.prototype.start = function(callback) {

  if (!this.topic||!this.dataUrl) { logger.error('Critical Error! Missing config!'); return; }
  logger.info('Initializing NSQ Publisher...');

  const w = new nsq.Writer(this.dataUrl, this.dataTcpPort);
  var count = 0;

  w.connect();
  w.on('ready', () => {
    logger.info('NSQ Writer Ready!');
    this.nsqw = w;
  });

  w.on('closed', () => {
    logger.error('NSQ Writer closed!');
    if (count < this.retries) {
	    logger.info('Reconnecting in '+this.timeout+'');
	    setTimeout(function(){ w.connect(); }, this.timeout);
    } else {
	logger.error('Giving up! Attempted:',this.retries);
   }