How to keep previous cached data when erroring

[IGassmann]

Let's say I have a page with a todo list that polls the list every 2s so that the list is always fresh:

import { useEffect } from 'react';
import { useQuery } from 'urql';

function Todos() {
  const [result, reexecuteQuery] = useQuery({
    query: TodosListQuery,
  });

  useEffect(() => {
    if (result.fetching) return;

    const timeoutID = setTimeout(() => {
      reexecuteQuery({ requestPolicy: 'network-only' });
    }, 2_000);

    return () => clearTimeout(timeoutID);
  }, [result.fetching, reexecuteQuery]);

  // ...
};

The query runs on the first time successfully, but on the second query, we get an error. This currently results in result.data getting set to undefined (if it's a network error) after the second query.

How can we still display the data cached by the previous query when an error occurs in a subsequent query?

I guess I could use the offline exchange, but that requires switching to Graphcache and doesn't cover the situation where we get a non-network error.