Method UseQuery

Namespace

Velvet

Assembly

Velvet.Docs.dll

UseQuery<T>(QueryOptions<T>, QueryClient?)

UseQuery<TQueryFnData, TData>(QueryOptions<TQueryFnData, TData>, QueryClient?) for a query whose result holds the data its query function returns.

public static QueryResult<T> UseQuery<T>(QueryOptions<T> options, QueryClient? client = null)

Parameters

options QueryOptions<T>

The key, the query function, and the options QueryOptions<TQueryFnData, TData> lists.

client QueryClient

The client to read; null reads the one Ref provides, and throws when no Provider supplies one.

Returns

QueryResult<T>

The entry's state as this render reads it.

Type Parameters

T

The query's data type. Every query sharing a key must use the same one.

UseQuery<TQueryFnData, TData>(QueryOptions<TQueryFnData, TData>, QueryClient?)

TanStack Query's useQuery. Reads the entry options' key names in a QueryClient, fetches it with the options' query function when it has no data or its data is stale, and re-renders the component when a property of the result it reads changes. Components reading one key share one entry and one request in flight, and the entry keeps its result after they unmount, so a component mounting over it later renders that result at once.

public static QueryResult<TData> UseQuery<TQueryFnData, TData>(QueryOptions<TQueryFnData, TData> options, QueryClient? client = null)

Parameters

options QueryOptions<TQueryFnData, TData>

The key, the query function, and the options QueryOptions<TQueryFnData, TData> lists.

client QueryClient

The client to read; null reads the one Ref provides, and throws when no Provider supplies one.

Returns

QueryResult<TData>

The entry's state as this render reads it.

Type Parameters

TQueryFnData

The entry's data type. Every query sharing a key must use the same one.

TData

The result's data type, which Select makes.

Remarks

Not a Suspense hook: a query with no data yet returns Pending rather than suspending, as useQuery does. Use<T>(Func<CancellationToken, VelvetTask<T>>, object?) stays the cache-less use().

The component subscribes in a passive effect, as useQuery does, and a fetch that mounting starts begins there. A change of key moves the subscription to the new key's entry: the result shows that entry's data, or none, and nothing the old key's request delivers afterwards.

A failed request runs again up to Retry times before the failure is the entry's error, and a request that lands is shared structurally with the data the entry held (StructuralSharing), as useQuery does.