Query

A popular pattern popularised by react-query and swr is to use a stale-while-revalidate pattern. Impact enables this pattern with its query primitive.

import { query } from "@impact-react/signals";
import { createApi } from "./api";

function AppStore() {
  const api = createApi();
  const [itemsQuery, invalidateItems] = query(() => api.getItems());

  return {
    itemsQuery,
    invalidateItems,
  };
}

The itemsQuery is a signal of the promise and state of the query:

const appStore = useAppStore();
const items = appStore.itemsQuery();

items.promise; // The observable promise
item.state; // idle, fetching or refetching