@langchain/core/dist/callbacks/dispatch/web.js

Core LangChain.js abstractions and schemas

import { getCallbackManagerForConfig } from "../../runnables/config.js";

//#region src/callbacks/dispatch/web.ts
/**
* Dispatch a custom event. Requires an explicit config object.
* @param name The name of the custom event.
* @param payload The data for the custom event.
*   Ideally should be JSON serializable to avoid serialization issues downstream, but not enforced.
* @param config Config object.
*
* @example
* ```typescript
* import { dispatchCustomEvent } from "@langchain/core/callbacks/dispatch";
*
* const foo = RunnableLambda.from(async (input: string, config?: RunnableConfig) => {
*   await dispatchCustomEvent(
*     "my_custom_event",
*     { arbitraryField: "someval" },
*     config
*   );
*   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 })
* ```
*/
async function dispatchCustomEvent(name, payload, config) {
	if (config === void 0) throw new Error([
		"Unable to dispatch a custom event without a parent run id.",
		`"dispatchCustomEvent" can only be called from within an existing run (e.g.,`,
		"inside a tool or a RunnableLambda).",
		`\n\nIf you continue to see this error, please import from "@langchain/core/callbacks/dispatch/web"`,
		"and explicitly pass in a config parameter.",
		`\n\nOr, if you are calling this from a custom tool, ensure you're using the "tool" helper constructor as documented here:`,
		"\n  |",
		"\n  └-> https://js.langchain.com/docs/how_to/custom_tools#tool-function",
		"\n"
	].join(" "));
	const callbackManager = await getCallbackManagerForConfig(config);
	const parentRunId = callbackManager?.getParentRunId();
	if (callbackManager !== void 0 && parentRunId !== void 0) await callbackManager.handleCustomEvent?.(name, payload, parentRunId);
}

//#endregion
export { dispatchCustomEvent };
//# sourceMappingURL=web.js.map