Function dispatchCustomEvent

Dispatch a custom event.

Note: this method is only supported in non-web environments due to usage of async_hooks to infer config.

If you are using this method in the browser, please import and use from "@langchain/core/callbacks/dispatch/web".

Example

import { dispatchCustomEvent } from "@langchain/core/callbacks/dispatch";

const foo = RunnableLambda.from(async (input: string) => {
  await dispatchCustomEvent("my_custom_event", { arbitraryField: "someval" });
  return input;
});

const callbacks = [{
  handleCustomEvent: (eventName: string, payload: any) => {
    // Logs "my_custom_event" and { arbitraryField: "someval" }
    console.log(eventName, payload);
  }
}];

await foo.invoke("hi", { callbacks })
Copy