Event Iterator in oRPC Clients

An Event Iterator in oRPC behaves like an AsyncGenerator. Simply iterate over it and await each event.

Basic Usage

const iterator = await client.streaming()

for await (const event of iterator) {
  console.log(event.message)
}

Stopping the Stream Manually

Call .return() on the iterator to gracefully end the stream.

const iterator = await client.streaming()

setTimeout(async () => {
  // Stop the stream after 1 second
  await iterator.return()
}, 1000)

for await (const event of iterator) {
  console.log(event.message)
}

Error Handling

INFO

Unlike traditional SSE, the Event Iterator does not automatically retry on error. To enable automatic retries, refer to the Client Retry Plugin.

const iterator = await client.streaming()

try {
  for await (const event of iterator) {
    console.log(event.message)
  }
}
catch (error) {
  if (error instanceof ORPCError) {
    // Handle the error here
  }
}

INFO

Errors thrown by the server can be instances of ORPCError.

Using consumeEventIterator

oRPC provides a utility function consumeEventIterator to consume an event iterator with lifecycle callbacks.

import { consumeEventIterator } from '@orpc/client'

const cancel = consumeEventIterator(client.streaming(), {
  onEvent: (event) => {
    console.log(event.message)
  },
  onError: (error) => {
    console.error(error)
  },
  onSuccess: (value) => {
    console.log(value)
  },
  onFinish: (state) => {
    console.log(state)
  },
})

setTimeout(async () => {
  // Stop the stream after 1 second
  await cancel()
}, 1000)

INFO

This utility accepts both promises and event iterators. Passing a promise directly lets it infer correct error type.