Cache Event Listeners with the JavaScript Client

What You Will Learn

How to register event listeners on a cache to receive notifications when entries are created, modified, or removed.

Prerequisites

Node.js 22+
An Infinispan Server running on localhost:11222

Start an Infinispan Server with Docker or Podman:

docker run -it --rm -p 11222:11222 -e USER=admin -e PASS=password quay.io/infinispan/server:latest

Tip	You can replace `docker` with `podman` in the command above if you use Podman.

Step 1: Register a Listener

Add a listener for create events. The returned listenerId is used to add more event types to the same listener:

const listenerId = await client.addListener('create', (key, version, id) => {
    console.log('[CREATE] key=' + key);
});

Step 2: Add More Event Types

await client.addListener('modify', (key, version, id) => {
    console.log('[MODIFY] key=' + key);
}, {listenerId: listenerId});

await client.addListener('remove', (key, id) => {
    console.log('[REMOVE] key=' + key);
}, {listenerId: listenerId});

Step 3: Trigger Events

Cache operations now trigger the registered callbacks:

await client.put('player1', 'Mario');   // triggers CREATE
await client.replace('player1', 'Peach'); // triggers MODIFY
await client.remove('player1');          // triggers REMOVE

Step 4: Remove the Listener

Remove the listener to stop receiving events:

await client.removeListener(listenerId);

Step 5: Run the Tutorial

npm run listeners

You should see output like:

Listener registered: <listener-id>
[CREATE] key=player1
[CREATE] key=player2
[MODIFY] key=player1
[REMOVE] key=player2

Listener removed.
No events after listener removal.

What’s Next

Basic cache operations for standard cache usage
Near caching for client-side caching with server invalidation