declare function listenEvent<T extends unknown = any>(clientId: string, topicName: string, fn: (data: T) => void): () => void;
Subscribes to a custom event on the swarm bus service and executes a callback when the event is received.
This function sets up a listener for events with a specified topic on the swarm's bus service, invoking the provided callback with the event's
payload when triggered. It is wrapped in beginContext for a clean execution environment, logs the operation if enabled, and enforces restrictions
on reserved topic names (defined in DISALLOWED_EVENT_SOURCE_LIST). The callback is queued to ensure sequential processing of events. The function
supports a wildcard client ID ("*") for listening to all clients or validates a specific client session. It returns an unsubscribe function to stop
listening.
| Parameter | Description |
|---|---|
clientId |
The ID of the client to listen for events from, or "*" to listen to all clients. |
topicName |
The name of the event topic to subscribe to (must not be a reserved source). |
fn |
The callback function to execute when the event is received, passed the event payload. |