Ably Queue with callback

const amqp = require('amqplib/callback_api');
const Ably = require('ably')


const url = 'amqps://APPID.KEYID:[email protected]/shared'
const queue = 'UATwBQ:example-queue'

function actionMessage(message) {
  console.log(message)
}

function handleError(error) {
  console.error(error)
}

amqp.connect(url, (err, conn) => {
  if (err) {
    return handleError(err)
  }


  /* Opens a channel for communication. The word channel is overloaded
     and this has nothing to do with pub/sub channels */
  conn.createChannel((err, ch) => {
    if (err) {
      return handleError(err)
    }


    /* Wait for messages published to the Ably Queue */
    ch.consume(queue, (item) => {
      let decodedEnvelope = JSON.parse(item.content)

      Ably.Realtime.Message.fromEncodedArray(decodedEnvelope.messages).then((messages) => {

        /* The envelope messages attribute will only contain one message. However,
           in future versions, we may allow optional bundling of messages into a
           single queue message and as such this attribute is an Array to support
           that in future */
        messages.forEach((message) => {
          actionMessage(message)
        })

        /* ACK (success) so that message is removed from queue */
        ch.ack(item)
      })
    })
  })
})