Function createBaseQuery

packages/svelte-query/src/createBaseQuery.svelte.ts:19–129

(
  options: Accessor<
    CreateBaseQueryOptions<TQueryFnData, TError, TData, TQueryData, TQueryKey>
  >,
  Observer: typeof QueryObserver,
  queryClient?: Accessor<QueryClient>,
)

 * @param queryClient - Custom query client which overrides provider
 */
export function createBaseQuery<
  TQueryFnData,
  TError,
  TData,
  TQueryData,
  TQueryKey extends QueryKey,
>(
  options: Accessor<
    CreateBaseQueryOptions<TQueryFnData, TError, TData, TQueryData, TQueryKey>
  >,
  Observer: typeof QueryObserver,
  queryClient?: Accessor<QueryClient>,
): CreateBaseQueryResult<TData, TError> {
  /** Load query client */
  const client = $derived(useQueryClient(queryClient?.()))
  const isRestoring = useIsRestoring()

  const resolvedOptions = $derived.by(() => {
    const opts = client.defaultQueryOptions(options())
    opts._optimisticResults = isRestoring.current ? 'isRestoring' : 'optimistic'
    return opts
  })

  /** Creates the observer */
  // svelte-ignore state_referenced_locally - intentional, initial value
  let observer = $state(
    new Observer<TQueryFnData, TError, TData, TQueryData, TQueryKey>(
      client,
      resolvedOptions,
    ),
  )
  watchChanges(
    () => client,
    'pre',
    () => {
      observer = new Observer<
        TQueryFnData,
        TError,
        TData,
        TQueryData,
        TQueryKey
      >(client, resolvedOptions)
    },
  )

  function createResult() {
    const result = observer.getOptimisticResult(resolvedOptions)
    return !resolvedOptions.notifyOnChangeProps
      ? observer.trackResult(result)
      : result
  }
  const [query, update] = createRawRef(
    // svelte-ignore state_referenced_locally - intentional, initial value
    createResult(),
  )

  // The following is convoluted but necessary:
  // Call eagerly so subscription happens on the server and on suspended branches in the client...