TanStack Query (React Query): Handling HTTP Requests with EaseEntry 10 of 10

Summary

Concept	TanStack Query (React)	Angular (built-in)
Setup	`QueryClient` + `<QueryClientProvider>`	`provideHttpClient()`
Read data	`useQuery({ queryKey, queryFn })`	`rxResource({ params, stream })` / `httpResource()`
State	`data`, `isPending`, `isLoading`, `isError`, `error`	`value()`, `isLoading()`, `error()`, `status()`
Manual refetch	`refetch()`	`reload()`
Cache	`QueryClient`, keyed by `queryKey`	Root service with signals
Freshness	`staleTime`	Timestamp check in service
Cache cleanup	`gcTime`	Service lifetime
Parameters	Dynamic `queryKey`	`params` signal
Cancellation	`signal` → `fetch`	Automatic (unsubscribe) / `abortSignal`
Conditional	`enabled`	`params` returns `undefined`
Write data	`useMutation` + `mutate()`	Service call + `subscribe()`
After write	`invalidateQueries({ queryKey })`	Version signal / `reload()`
Optimistic	`onMutate` + `setQueryData` + rollback in `onError`	`value.set()` + rollback in `error`
Final resync	`onSettled` → `invalidateQueries`	`finalize` → `reload()`

TanStack Query turns server data into a shared, self-refreshing cache: queries read by key, mutations write and invalidate, and optimistic updates edit the cache directly with a rollback plan. Angular covers the same needs with built-in pieces: HttpClient services for requests, rxResource() for signal-based request state, and root services with signals when data must be shared, cached, or updated optimistically.