Sample JS code to illustrate issue with deferred msgs received in ReceiveAndDelete mode

deferred_receiveAndDelete_mode.js

/*
Set up instructions:
- Ensure you have Nodejs installed, else install from https://nodejs.org/en/
- Copy the this file to an empty folder
- Run `npm install @azure/service-bus` in this empty folder
- Add your connection string and partitioned queue (no sessions) details in the sample (use empty queue)
- Run `node deferred_receiveAndDelete_mode.js` (if you have named the file differently, use that name)
- Change the queue to other variations (unparitioned, sessions etc) and see the difference
*/

const { ServiceBusClient, ReceiveMode } = require("@azure/service-bus");

// Use empty queue
const connectionString = "";
const queueName = "";

async function main() {
  const ns = ServiceBusClient.createFromConnectionString(connectionString);
  const client = ns.createQueueClient(queueName);

  try {
    // Send a message
    const sender = client.createSender();
    const msgBody = "hello" + Math.random();
    await sender.send({ body: msgBody });
    console.log(`Sent msg with body: ${msgBody}`);

    // Receive and defer the message
    const receiver1 = client.createReceiver(ReceiveMode.peekLock);
    const [msg] = await receiver1.receiveMessages(1);
    let sequenceNumber;
    if (msg) {
      console.log(`Deferring msg with body: ${msg.body}`);
      sequenceNumber = msg.sequenceNumber;
      await msg.defer();
    }
    await receiver1.close();

    // Recieve deferred msg in ReceiveAndDelete mode
    const receiver2 = client.createReceiver(ReceiveMode.receiveAndDelete);
    const deferredMsg = await receiver2.receiveDeferredMessage(sequenceNumber);
    if (deferredMsg) {
      console.log(
        `Received deferred msg with body: ${deferredMsg.body} and lockToken: ${
          deferredMsg.lockToken
        }`
      );
    }

    // Check contents of the queue
    const peekedMsgs = await client.peek(1);
    if (peekedMsgs.length) {
      console.log("Oh no! There are messages left in the queue!!");
    } else {
      console.log("All good");
    }
  } finally {
    await ns.close();
  }
}

main().catch(err => {
  console.log("Error occurred: ", err);
});