fromQuery

Description#

Bridge that projects a TanStack Query result onto CngxAsyncState<T>.

Reads the query's signal-bag and maps TanStack's status / fetchStatus pair onto the cngx AsyncStatus union, then hands the derived signals to buildAsyncStateView - the same single-source-of-truth kernel every other producer uses. No injection context is required (only computed()), and no boolean view is re-derived here.

Status mapping:

• error + fetching -> loading (no retained data) / refreshing (data retained) - a retry out of error reports busy again
• error + idle/paused -> error
• success + fetching -> refreshing (background refetch, data visible)
• success + idle/paused -> success
• pending + fetching -> loading (first load, no data yet)
• pending + idle/paused -> idle (disabled or paused query)

With placeholderData, TanStack reports success + fetching while the first real load runs - that maps to refreshing over the placeholder, deliberately suppressing the skeleton (the intended TanStack UX).

isFirstLoad is !hadSuccess, the kernel-recommended query semantics: a failed or retrying first load stays isFirstLoad === true until data actually arrived once. Bind dataUpdatedAt for the exact latch; without it the bridge falls back to status === 'success' or retained data. Two deliberate divergences from fromResource: a settled first-load error stays first-load here (fromResource flips false on error), and the latch is derived, so a query reset / key swap (dataUpdatedAt back to 0) returns to first-load instead of staying latched forever.

private readonly query = injectQuery(() => ({
  queryKey: ['users', this.filter()],
  queryFn: () => fetchUsers(this.filter()),
}));

readonly users = fromQuery(this.query);
// users.status(), users.data(), users.isFirstLoad() - all work
// <cngx-async-container [state]="users"> - direct binding