Async state
The standalone createAsync operation exposes one immutable snapshot:
type AsyncState<Data, Empty = null> = {
status: "idle" | "loading" | "success" | "error";
data: Data | Empty;
error: unknown | null;
isLoading: boolean;
};
The fields are deliberately separate. A request can keep useful data while reporting an error, and isLoading can remain true while another concurrent request completes.
Lifecycle
| Event | status | error | isLoading |
|---|---|---|---|
| Created or reset | idle | null | false |
| Execute | loading | null | true |
| Resolve | success | null | Depends on active requests |
| Reject | error | Rejection value | Depends on active requests |
| Abort | idle | null | false |
By default, failures preserve the previous data. Use dataOnError when a failure should replace it:
const operation = createAsync(loadItems, {
initialData: [],
dataOnError: () => [],
});
Immutable snapshots
Core snapshots are frozen and replaced as a unit, so consumers can compare references. Framework adapters manage their own state with React hooks, Vue refs, or Svelte stores; they do not subscribe to and mirror core snapshots.