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WebSocket

This section will cover how to create a Websocket connection and subscribe to EventSub events with it.

Creating a WebSocket connection

To start a WebSocket connection we need to create a new instance of WebSocketConnection.

websocket.ts
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import { WebSocketConnection } from '@twitchfy/eventsub'
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const connection = new WebSocketConnection({
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    clientId: 'clientId',
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    clientSecret: 'clientSecret',
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    userToken: 'myUserToken',
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    maintainSubscriptions: false
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})
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connection.connect();

To wait until the connection is fully operational you can either wait until the connect method promise is resolved or listen to ConnectionReady event.

websocket.ts
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import { WebSocketConnection, Events } from '@twitchfy/eventsub'
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const connection = new WebSocketConnection({
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    clientId: 'clientId',
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    clientSecret: 'clientSecret',
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    userToken: 'myUserToken',
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    maintainSubscriptions: false
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})
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connection.connect()
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.then(() => console.log('Connection ready'));
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connection.on(Events.ConnectionReady, () => {
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    console.log('Connection ready x2')
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})

Subscribing to events

Having created a functional WebSocket connection it is time to subscribe to our first event.

This example will show how to subscribe to a StreamOnline event.

websocket.ts
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import { WebSocketConnection, Events, SubscriptionTypes } from '@twitchfy/eventsub'
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const connection = new WebSocketConnection({
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    clientId: 'clientId',
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    clientSecret: 'clientSecret',
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    userToken: 'myUserToken',
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    maintainSubscriptions: false
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})
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connection.connect()
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.then(() => console.log('Connection ready'));
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connection.on(Events.ConnectionReady, async() => {
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    console.log('Connection ready x2');
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    await connection.subscribe({ type: SubscriptionTypes.StreamOnline, options: {
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        broadcaster_user_id: 'userId'
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    }})
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})

Listening events

Now that you have created a new subscription we will listen to it and get notified whenever it is fired.

To achive this we can either use a callback using the onMessage function in the subscription object or using the SubscriptionMessage event.

websocket.ts
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import { WebSocketConnection, Events, SubscriptionTypes } from '@twitchfy/eventsub'
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const connection = new WebSocketConnection({
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    clientId: 'clientId',
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    clientSecret: 'clientSecret',
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    userToken: 'myUserToken',
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    maintainSubscriptions: false
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})
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connection.connect()
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.then(() => console.log('Connection ready'));
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connection.on(Events.ConnectionReady, async() => {
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    console.log('Connection ready x2');
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    const subscription = await connection.subscribe({ type: SubscriptionTypes.StreamOnline, options: {
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        broadcaster_user_id: 'userId'
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    }})
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    subscription.onMessage((message) => {
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        console.log(`${message.broadcaster.displayName} has started a stream at ${message.stream.startedAt.toLocaleDateString()}`)
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    })
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})

WebSocket Limits

Twitch limits the amount of connections and subscriptions you can create using WebSockets. The limits are listed in their official documentation. Here is a brief summary about them:

  • You can create up to 3 diffrent connections with the same clientId and userToken.
  • Each WebSocket connection can create up to 300 enabled subscriptions.
  • There is a max of 10 cost.
  • There is a limit of 3 subscriptions with the same type and options.

The limit is applied per userToken.