snapshot of https://github.com/TanStack/query.git (main, 2026-09-16; blobs > 131072B omitted)

docs/framework/preact/reference/functions/HydrationBoundary.md

@@ -0,0 +1,62 @@
+---
+id: HydrationBoundary
+title: HydrationBoundary
+---
+
+```ts
+function HydrationBoundary(__namedParameters): Element;
+```
+
+Defined in: [packages/preact-query/src/HydrationBoundary.tsx:87](https://github.com/TanStack/query/blob/main/packages/preact-query/src/HydrationBoundary.tsx#L87)
+
+`HydrationBoundary` adds a previously dehydrated state into the `queryClient` that would be returned by
+`useQueryClient()`. If the client already contains data, the new queries will be intelligently merged based on
+update timestamp.
+
+Note: Only `queries` can be dehydrated with an `HydrationBoundary`.
+
+## Parameters
+
+### \_\_namedParameters
+
+[`HydrationBoundaryProps`](../interfaces/HydrationBoundaryProps.md)
+
+## Returns
+
+`Element`
+
+The provided `children`, rendered unconditionally. New queries in `state` are hydrated into the
+cache during render; for queries already in the cache, only newer dehydrated data is hydrated, in an effect
+after commit.
+
+## Examples
+
+```tsx
+import { HydrationBoundary } from '@tanstack/preact-query'
+
+function App() {
+  return <HydrationBoundary state={dehydratedState}>...</HydrationBoundary>
+}
+```
+
+Server-side prefetch handed off to the client via `dehydrate`:
+```tsx
+import { HydrationBoundary, dehydrate, noop } from '@tanstack/preact-query'
+
+async function ServerComponent() {
+  const queryClient = getQueryClient()
+
+  await queryClient
+    .query({
+      queryKey: ['posts'],
+      queryFn: fetchPosts,
+    })
+    .catch(noop)
+
+  return (
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <Posts />
+    </HydrationBoundary>
+  )
+}
+```