| import * as React from 'react' |
| import ReactDOM from 'react-dom/client' |
| import { QueryClient, useQuery, useQueryClient } from '@tanstack/react-query' |
| import { PersistQueryClientProvider } from '@tanstack/react-query-persist-client' |
| import { createAsyncStoragePersister } from '@tanstack/query-async-storage-persister' |
| import { ReactQueryDevtools } from '@tanstack/react-query-devtools' |
|
|
| const queryClient = new QueryClient({ |
| defaultOptions: { |
| queries: { |
| gcTime: 1000 * 60 * 60 * 24, |
| }, |
| }, |
| }) |
|
|
| const persister = createAsyncStoragePersister({ |
| storage: window.localStorage, |
| }) |
|
|
| type Post = { |
| id: number |
| title: string |
| body: string |
| } |
|
|
| function usePosts() { |
| return useQuery({ |
| queryKey: ['posts'], |
| queryFn: async (): Promise<Array<Post>> => { |
| const response = await fetch('https://jsonplaceholder.typicode.com/posts') |
| return await response.json() |
| }, |
| }) |
| } |
|
|
| function Posts({ |
| setPostId, |
| }: { |
| setPostId: React.Dispatch<React.SetStateAction<number>> |
| }) { |
| const queryClient = useQueryClient() |
| const { status, data, error, isFetching } = usePosts() |
|
|
| return ( |
| <div> |
| <h1>Posts</h1> |
| <div> |
| {status === 'pending' ? ( |
| 'Loading...' |
| ) : status === 'error' ? ( |
| <span>Error: {error.message}</span> |
| ) : ( |
| <> |
| <div> |
| {data.map((post) => ( |
| <p key={post.id}> |
| <a |
| onClick={() => setPostId(post.id)} |
| href="#" |
| style={ |
| // We can access the query data here to show bold links for |
| // ones that are cached |
| queryClient.getQueryData(['post', post.id]) |
| ? { |
| fontWeight: 'bold', |
| color: 'green', |
| } |
| : {} |
| } |
| > |
| {post.title} |
| </a> |
| </p> |
| ))} |
| </div> |
| <div>{isFetching ? 'Background Updating...' : ' '}</div> |
| </> |
| )} |
| </div> |
| </div> |
| ) |
| } |
|
|
| const getPostById = async (id: number): Promise<Post> => { |
| const response = await fetch( |
| `https://jsonplaceholder.typicode.com/posts/${id}`, |
| ) |
| return await response.json() |
| } |
|
|
| function usePost(postId: number) { |
| return useQuery({ |
| queryKey: ['post', postId], |
| queryFn: () => getPostById(postId), |
| enabled: !!postId, |
| }) |
| } |
|
|
| function Post({ |
| postId, |
| setPostId, |
| }: { |
| postId: number |
| setPostId: React.Dispatch<React.SetStateAction<number>> |
| }) { |
| const { status, data, error, isFetching } = usePost(postId) |
|
|
| return ( |
| <div> |
| <div> |
| <a onClick={() => setPostId(-1)} href="#"> |
| Back |
| </a> |
| </div> |
| {!postId || status === 'pending' ? ( |
| 'Loading...' |
| ) : status === 'error' ? ( |
| <span>Error: {error.message}</span> |
| ) : ( |
| <> |
| <h1>{data.title}</h1> |
| <div> |
| <p>{data.body}</p> |
| </div> |
| <div>{isFetching ? 'Background Updating...' : ' '}</div> |
| </> |
| )} |
| </div> |
| ) |
| } |
|
|
| function App() { |
| const [postId, setPostId] = React.useState(-1) |
|
|
| return ( |
| <PersistQueryClientProvider |
| client={queryClient} |
| persistOptions={{ persister }} |
| > |
| <p> |
| As you visit the posts below, you will notice them in a loading state |
| the first time you load them. However, after you return to this list and |
| click on any posts you have already visited again, you will see them |
| load instantly and background refresh right before your eyes!{' '} |
| <strong> |
| (You may need to throttle your network speed to simulate longer |
| loading sequences) |
| </strong> |
| </p> |
| {postId > -1 ? ( |
| <Post postId={postId} setPostId={setPostId} /> |
| ) : ( |
| <Posts setPostId={setPostId} /> |
| )} |
| <ReactQueryDevtools initialIsOpen /> |
| </PersistQueryClientProvider> |
| ) |
| } |
|
|
| const rootElement = document.getElementById('root') as HTMLElement |
| ReactDOM.createRoot(rootElement).render(<App />) |
|
|
