addEventsForMutations

Publishes an event after each successful create, update, delete, updateMany or deleteMany so other clients refresh. The write never fails because a publish failed.

addEventsForMutations wraps a data provider and publishes after its writes, so a change made here reaches the live views of every other client.

Signature

function addEventsForMutations<TProvider extends DataProvider>(
  base: TProvider,
  publisher: Pick<RealtimeTransport, "publish">,
  options?: AddEventsForMutationsOptions,
): TProvider
 
interface AddEventsForMutationsOptions {
  /** Called with each publish that rejected; the mutation still resolves. */
  onError?: (error: unknown) => void;
}

• base is the provider to wrap. The result is typed TProvider, so wrapping a RealtimeDataProvider keeps it one and every live hook still takes it.
• publisher needs only publish: pass a transport, or the wrapped provider itself.
• onError hears each rejected publish. An onError that throws is swallowed too.
• create, update, delete, updateMany and deleteMany are wrapped. Every other method is copied as it is, including the methods on the prototype chain of a class instance.

Returns

TProvider: the same verbs, each resolving after its publishes settle. A rejected publish goes to onError and never fails the write, because the write is already committed.

Each write publishes on these topics:

Those are the topics resourceTopic and recordTopic build, so a subscriber written by hand matches the wrapper. 1 and "1" give the same topic.

Leave the wrapper out when your server publishes for every write already, such as a database change feed: publishing twice refetches twice.

Example

import {
  addEventsForMutations,
  realtimeDataProvider,
  webSocketTransport,
} from "@chelone/core";
import { baseProvider } from "./baseProvider";
 
const transport = webSocketTransport({ url: "wss://api.example.com/realtime" });
 
export const dataProvider = addEventsForMutations(
  realtimeDataProvider(baseProvider, transport),
  transport,
  { onError: (error) => console.error("publish failed", error) },
);

See the realtime guide for the provider setup, the event payloads and the topics the live views listen on.