TLCustomMessageHandler • tldraw Docs

Handler function for custom application messages sent through the sync protocol. These are user-defined messages that can be sent between clients via the sync server, separate from the standard document synchronization messages.

type TLCustomMessageHandler = (this: null, data: any) => void

Example

const customMessageHandler: TLCustomMessageHandler = (data) => {
  if (data.type === 'user_joined') {
    console.log(`${data.username} joined the session`)
    showToast(`${data.username} is now collaborating`)
  }
}

const syncClient = new TLSyncClient({
  // ... other config
  onCustomMessageReceived: customMessageHandler,
})

Parameters

Name	Description
`data`	Custom message payload (application-defined structure)