Feature/hydrate promises

docs/config.json

@@ -849,9 +849,13 @@
               "to": "framework/react/examples/rick-morty"
             },
             {
-              "label": "Next.js",
+              "label": "Next.js Pages",
               "to": "framework/react/examples/nextjs"
             },
+            {
+              "label": "Next.js app with prefetching",
+              "to": "framework/react/examples/nextjs-app-prefetching"
+            },
             {
               "label": "Next.js app with streaming",
               "to": "framework/react/examples/nextjs-suspense-streaming"

docs/framework/react/guides/advanced-ssr.md

@@ -52,7 +52,7 @@ function getQueryClient() {
     return makeQueryClient()
   } else {
     // Browser: make a new query client if we don't already have one
-    // This is very important so we don't re-make a new client if React
+    // This is very important, so we don't re-make a new client if React
     // suspends during the initial render. This may not be needed if we
     // have a suspense boundary BELOW the creation of the query client
     if (!browserQueryClient) browserQueryClient = makeQueryClient()
@@ -354,9 +354,80 @@ The Next.js app router automatically streams any part of the application that is
 
 With the prefetching patterns described above, React Query is perfectly compatible with this form of streaming. As the data for each Suspense boundary resolves, Next.js can render and stream the finished content to the browser. This works even if you are using `useQuery` as outlined above because the suspending actually happens when you `await` the prefetch.
 
-Note that right now, you have to await all prefetches for this to work. This means all prefetches are considered critical content and will block that Suspense boundary.
+As of React Query v5.40.0, you don't have to `await` all prefetches for this to work, as `pending` Queries can also be dehydrated and sent to the client. This lets you kick off prefetches as early as possible without letting them block an entire Suspense boundary, and streams the _data_ to the client as the query finishes. This can be useful for example if you want to prefetch some content that is only visible after some user interaction, or say if you want to `await` and render the first page of an infinite query, but start prefetching page 2 without blocking rendering.
 
-As an aside, in the future it might be possible to skip the await for "optional" prefetches that are not critical for this Suspense boundary. This would let you kick off prefetches as early as possible without letting them block an entire Suspense boundary, and streaming the _data_ to the client as the query finishes. This could be useful for example if you want to prefetch some content that is only visible after some user interaction, or say if you want to await and render the first page of an infinite query, but start prefetching page 2 without blocking rendering.
+To make this work, we have to instruct the `queryClient` to also `dehydrate` pending Queries. We can do this globally, or by passing that option directly to `hydrate`:
+
+```tsx
+// app/get-query-client.ts
+import { QueryClient, defaultShouldDehydrateQuery } from '@tanstack/react-query'
+
+function makeQueryClient() {
+  return new QueryClient({
+    defaultOptions: {
+      queries: {
+        staleTime: 60 * 1000,
+      },
+      dehydrate: {
+        // per default, only successful Queries are included,
+        // this includes pending Queries as well
+        shouldDehydrateQuery: (query) =>
+          defaultShouldDehydrateQuery(query) ||
+          query.state.status === 'pending',
+      },
+    },
+  })
+}
+```
+
+> Note: This works in NextJs and Server Components because React can serialize Promises over the wire when you pass them down to Client Components.
+
+Then, all we need to do is provide a `HydrationBoundary`, but we don't need to `await` prefetches anymore:
+
+```tsx
+// app/posts/page.jsx
+import {
+  dehydrate,
+  HydrationBoundary,
+  QueryClient,
+} from '@tanstack/react-query'
+import { getQueryClient } from './get-query-client'
+import Posts from './posts'
+
+// the function doesn't need to be `async` because we don't `await` anything
+export default function PostsPage() {
+  const queryClient = getQueryClient()
+
+  // look ma, no await
+  queryClient.prefetchQuery({
+    queryKey: ['posts'],
+    queryFn: getPosts,
+  })
+
+  return (
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <Posts />
+    </HydrationBoundary>
+  )
+}
+```
+
+On the client, the Promise will be put into the QueryCache for us. That means we can now call `useSuspenseQuery` inside the `Posts` component to "use" that Promise (which was created on the Server):
+
+```tsx
+// app/posts/posts.tsx
+'use client'
+
+export default function Posts() {
+  const { data } = useSuspenseQuery({ queryKey: ['posts'], queryFn: getPosts })
+
+  // ...
+}
+```
+
+> Note that you could also `useQuery` instead of `useSuspenseQuery`, and the Promise would still be picked up correctly. However, NextJs won't suspend in that case and the component will render in the `pending` status, which also opts out of server rendering the content.
+
+For more information, check out the [Next.js App with Prefetching Example](../../examples/nextjs-app-prefetching).
 
 ## Experimental streaming without prefetching in Next.js
 
@@ -394,8 +465,8 @@ function getQueryClient() {
     return makeQueryClient()
   } else {
     // Browser: make a new query client if we don't already have one
-    // This is very important so we don't re-make a new client if React
-    // supsends during the initial render. This may not be needed if we
+    // This is very important, so we don't re-make a new client if React
+    // suspends during the initial render. This may not be needed if we
     // have a suspense boundary BELOW the creation of the query client
     if (!browserQueryClient) browserQueryClient = makeQueryClient()
     return browserQueryClient

docs/framework/react/guides/suspense.md

@@ -142,8 +142,8 @@ function getQueryClient() {
     return makeQueryClient()
   } else {
     // Browser: make a new query client if we don't already have one
-    // This is very important so we don't re-make a new client if React
-    // supsends during the initial render. This may not be needed if we
+    // This is very important, so we don't re-make a new client if React
+    // suspends during the initial render. This may not be needed if we
     // have a suspense boundary BELOW the creation of the query client
     if (!browserQueryClient) browserQueryClient = makeQueryClient()
     return browserQueryClient

docs/framework/react/reference/hydration.md

@@ -45,7 +45,7 @@ const dehydratedState = dehydrate(queryClient, {
   - You **should not** rely on the exact format of this response, it is not part of the public API and can change at any time
   - This result is not in serialized form, you need to do that yourself if desired
 
-### limitations
+### Limitations
 
 Some storage systems (such as browser [Web Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API)) require values to be JSON serializable. If you need to dehydrate values that are not automatically serializable to JSON (like `Error` or `undefined`), you have to serialize them for yourself. Since only successful queries are included per default, to also include `Errors`, you have to provide `shouldDehydrateQuery`, e.g.:
 
@@ -88,7 +88,7 @@ hydrate(queryClient, dehydratedState, options)
 
 ### Limitations
 
-If the queries included in dehydration already exist in the queryCache, `hydrate` does not overwrite them and they will be **silently** discarded.
+If the queries you're trying to hydrate already exist in the queryCache, `hydrate` will only overwrite them if the data is newer than the data present in the cache. Otherwise, it will **not** get applied.
 
 [//]: # 'HydrationBoundary'
 
@@ -104,6 +104,8 @@ function App() {
 }
 ```
 
+> Note: Only `queries` can be dehydrated with an `HydrationBoundary`.
+
 **Options**
 
 - `state: DehydratedState`

docs/reference/QueryClient.md

@@ -62,6 +62,7 @@ Its available methods are:
 - `defaultOptions?: DefaultOptions`
   - Optional
   - Define defaults for all queries and mutations using this queryClient.
+  - You can also define defaults to be used for [hydration](../../framework/react/reference/hydration.md)
 
 ## `queryClient.fetchQuery`
 

examples/react/nextjs-app-prefetching/.eslintrc.cjs

@@ -0,0 +1,9 @@
+/** @type {import('eslint').Linter.Config} */
+module.exports = {
+  extends: ['plugin:react/jsx-runtime', 'plugin:react-hooks/recommended'],
+  settings: {
+    react: {
+      version: 'detect',
+    },
+  },
+}

examples/react/nextjs-app-prefetching/.gitignore

@@ -0,0 +1,35 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# local env files
+.env*.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts

examples/react/nextjs-app-prefetching/README.md

@@ -0,0 +1,34 @@
+This is a [Next.js](https://nextjs.org/) project bootstrapped with [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app).
+
+## Getting Started
+
+First, run the development server:
+
+```bash
+npm run dev
+# or
+yarn dev
+# or
+pnpm dev
+```
+
+Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+
+You can start editing the page by modifying `app/page.tsx`. The page auto-updates as you edit the file.
+
+This project uses [`next/font`](https://nextjs.org/docs/basic-features/font-optimization) to automatically optimize and load Inter, a custom Google Font.
+
+## Learn More
+
+To learn more about Next.js, take a look at the following resources:
+
+- [Next.js Documentation](https://nextjs.org/docs) - learn about Next.js features and API.
+- [Learn Next.js](https://nextjs.org/learn) - an interactive Next.js tutorial.
+
+You can check out [the Next.js GitHub repository](https://github.com/vercel/next.js/) - your feedback and contributions are welcome!
+
+## Deploy on Vercel
+
+The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
+
+Check out our [Next.js deployment documentation](https://nextjs.org/docs/deployment) for more details.

examples/react/nextjs-app-prefetching/app/get-query-client.ts

@@ -0,0 +1,33 @@
+import { QueryClient, defaultShouldDehydrateQuery } from '@tanstack/react-query'
+
+function makeQueryClient() {
+  return new QueryClient({
+    defaultOptions: {
+      queries: {
+        staleTime: 60 * 1000,
+      },
+      dehydrate: {
+        // include pending queries in dehydration
+        shouldDehydrateQuery: (query) =>
+          defaultShouldDehydrateQuery(query) ||
+          query.state.status === 'pending',
+      },
+    },
+  })
+}
+
+let browserQueryClient: QueryClient | undefined = undefined
+
+export function getQueryClient() {
+  if (typeof window === 'undefined') {
+    // Server: always make a new query client
+    return makeQueryClient()
+  } else {
+    // Browser: make a new query client if we don't already have one
+    // This is very important, so we don't re-make a new client if React
+    // suspends during the initial render. This may not be needed if we
+    // have a suspense boundary BELOW the creation of the query client
+    if (!browserQueryClient) browserQueryClient = makeQueryClient()
+    return browserQueryClient
+  }
+}

examples/react/nextjs-app-prefetching/app/layout.tsx

@@ -0,0 +1,22 @@
+import Providers from './providers'
+import type React from 'react'
+import type { Metadata } from 'next'
+
+export const metadata: Metadata = {
+  title: 'Create Next App',
+  description: 'Generated by create next app',
+}
+
+export default function RootLayout({
+  children,
+}: {
+  children: React.ReactNode
+}) {
+  return (
+    <html lang="en">
+      <body>
+        <Providers>{children}</Providers>
+      </body>
+    </html>
+  )
+}

examples/react/nextjs-app-prefetching/app/page.tsx

@@ -0,0 +1,20 @@
+import React from 'react'
+import { HydrationBoundary, dehydrate } from '@tanstack/react-query'
+import { pokemonOptions } from '@/app/pokemon'
+import { getQueryClient } from '@/app/get-query-client'
+import { PokemonInfo } from './pokemon-info'
+
+export default function Home() {
+  const queryClient = getQueryClient()
+
+  void queryClient.prefetchQuery(pokemonOptions)
+
+  return (
+    <main>
+      <h1>Pokemon Info</h1>
+      <HydrationBoundary state={dehydrate(queryClient)}>
+        <PokemonInfo />
+      </HydrationBoundary>
+    </main>
+  )
+}

examples/react/nextjs-app-prefetching/app/pokemon-info.tsx

@@ -0,0 +1,18 @@
+'use client'
+
+import React from 'react'
+import { useSuspenseQuery } from '@tanstack/react-query'
+import { pokemonOptions } from '@/app/pokemon'
+
+export function PokemonInfo() {
+  const { data } = useSuspenseQuery(pokemonOptions)
+
+  return (
+    <div>
+      <figure>
+        <img src={data.sprites.front_shiny} height={200} alt={data.name} />
+        <h2>I'm {data.name}</h2>
+      </figure>
+    </div>
+  )
+}

examples/react/nextjs-app-prefetching/app/pokemon.ts

@@ -0,0 +1,10 @@
+import { queryOptions } from '@tanstack/react-query'
+
+export const pokemonOptions = queryOptions({
+  queryKey: ['pokemon'],
+  queryFn: async () => {
+    const response = await fetch('https://pokeapi.co/api/v2/pokemon/25')
+
+    return response.json()
+  },
+})

examples/react/nextjs-app-prefetching/app/providers.tsx

@@ -0,0 +1,16 @@
+'use client'
+import { QueryClientProvider } from '@tanstack/react-query'
+import { ReactQueryDevtools } from '@tanstack/react-query-devtools'
+import { getQueryClient } from '@/app/get-query-client'
+import type * as React from 'react'
+
+export default function Providers({ children }: { children: React.ReactNode }) {
+  const queryClient = getQueryClient()
+
+  return (
+    <QueryClientProvider client={queryClient}>
+      {children}
+      <ReactQueryDevtools />
+    </QueryClientProvider>
+  )
+}

examples/react/nextjs-app-prefetching/next.config.js

@@ -0,0 +1,8 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  eslint: {
+    ignoreDuringBuilds: true,
+  },
+}
+
+module.exports = nextConfig