Server-sent events

Operations returning text/event-stream produce a typed stream rather than a RequestResult. The client switches to the axios fetch adapter for these calls unless you set adapter yourself, because the default XHR adapter buffers the whole body.

Consume a stream

Read the EventStreamResult.stream with for await:

import { streamEvents } from './gen/clients/streamEvents'

const { stream } = await streamEvents({})

for await (const event of stream) {
  console.info(event.data)
}

data is typed from the operation's response schema. Each event also carries the optional SSE fields, so you can branch on the event name or read the id:

type ServerSentEvent<TData> = {
  data: TData
  event?: string
  id?: string
  retry?: number
}

The runtime parses each event's data as JSON when it is valid and keeps it as the raw string otherwise.

Stop early

Break out of the loop to stop reading. The underlying reader is canceled when the iterator finishes, so an early break releases the stream:

const { stream } = await streamEvents({})

for await (const event of stream) {
  if (event.event === 'done') break
  render(event.data)
}

To stop a stream from outside the loop, pass an AbortSignal and abort it. Aborting ends the request and the iteration:

const controller = new AbortController()
const { stream } = await streamEvents({ signal: controller.signal })

// elsewhere, for example on component unmount
controller.abort()

Read the response

Read status and headers from the native response before iterating:

const { stream, response } = await streamEvents({})

console.info(response.status) // 200
console.info(response.headers.get('x-stream-id'))

for await (const event of stream) {
  handle(event.data)
}

Handle errors

Catch non-2xx responses around the call and iteration, and rethrow other errors such as connection failures:

import { ResponseError } from './gen/.kubb/client'

try {
  const { stream } = await streamEvents({})
  for await (const event of stream) {
    handle(event.data)
  }
} catch (error) {
  if (!ResponseError.is(error)) throw error
  console.error('stream rejected', error.status)
}

A drop mid-stream ends the for await loop. Track the last event's id if you need to reconnect from where the stream stopped.

Server-sent events

Consume a stream

Stop early

Read the response

Handle errors

See also