Subscribing to Events
Events provide a mechanism to transfer data to connections that subscribe to them. They form the backbone of Relaybox services as an event-driven system.
Subscribing to All Events
When a connection joins a room, it can either process all data sent to the room or subscribe to specific events of interest. To subscribe to all events sent to a specific room, simply pass your event handler as the first argument when creating the subscription.
const myRoom = await relayBox.join('myRoom');
await myRoom.subscribe((data) => {
// All data sent to "myRoom" will be handled here
console.log(data)
});
This approach is useful if you are interested in receiving all events for a room. However, if you would prefer to receive only certain named events, the syntax is slightly different.
Subscribing to Named Events
When joining a room, it is common to subscribe to named events depending on the data you wish to receive.
const myRoom = await relayBox.join('myRoom');
await myRoom.subscribe('eventOne', (data) => {
// Only "eventOne" events will be received
console.log(data)
});
This method can reduce traffic and cost as it allows you to filter a subset of events. Unlike other systems, you will only be sent the events you are subscribed to, rather than subscriptions just acting as a filter at the room level.
