I need help dealing with errors!

[rossanodr]

I'm trying to learn how to use LangGraph, but I'm struggling with some beginner doubts.

I've been following LangChain tutorials on YouTube and came across this project: https://github.com/bracesproul/gen-ui-python.

I'm trying to handle errors in a specific part of the front end and encountered the following issue:

const eventHandlerOne = (
    streamEvent: StreamEvent,
    fields: EventHandlerFields
) => {
    try {
        const langGraphEvent: StreamEvent = streamEvent.data.chunk;
        console.log("langGraphEvent", langGraphEvent.error);

        if (!langGraphEvent) {
            return;
        }
        const { event, name, data } = langGraphEvent;
        if (event !== "on_chain_end") {
            return;
        }

    } catch (error) {
        console.log("error", error);
    }
};

In the example above, when I force an error, I get the result langGraphEvent Error
error TypeError: Cannot read properties of undefined (reading 'error').

However, the code presents typing errors:
Property 'error' does not exist on type 'StreamEvent'.ts(2339)

What is the ideal way to handle errors in langGraph cloud projects?