TanStack-Query
queryKey
How TanStack Query queryKey management evolved from inline arrays and constants to key factories and v5 queryOptions, with DataTag and invalidation.
How queryKey Comparison Works
How TanStack Query judges new queryKey arrays equal: hashKey serialization (key order, undefined, Map, cycles) and how filters compare key structure.
Placing ErrorBoundary
How many ErrorBoundaries to use and where, checked in source: what route, screen, and region each receive, one shared fallback, and retry conditions.
Why the Retry Button Does Nothing
Three cases where retry in a react-error-boundary fallback brings back the same fallback, checked in installed source, and how to clear each one.
Error Propagation
Throw the same error from seven places and only four reach an ErrorBoundary. This post traces where each kind actually propagates.