Quick Start

This example very briefly illustrates the 3 core concepts of React Query:

• Queries
• Mutations
• Query Invalidation

1 import {
2   useQuery,
3   useMutation,
4   useQueryClient,
5   QueryClient,
6   QueryClientProvider,
7 } from 'react-query'
8 import { getTodos, postTodo } from '../my-api'
9 
10 // Create a client
11 const queryClient = new QueryClient()
12 
13 function App() {
14   return (
15     // Provide the client to your App
16     <QueryClientProvider client={queryClient}>
17       <Todos />
18     </QueryClientProvider>
19   )
20 }
21 
22 function Todos() {
23   // Access the client
24   const queryClient = useQueryClient()
25 
26   // Queries
27   const query = useQuery(['todos'], getTodos)
28 
29   // Mutations
30   const mutation = useMutation(postTodo, {
31     onSuccess: () => {
32       // Invalidate and refetch
33       queryClient.invalidateQueries(['todos'])
34     },
35   })
36 
37   return (
38     <div>
39       <ul>
40         {query.data.map(todo => (
41           <li key={todo.id}>{todo.title}</li>
42         ))}
43       </ul>
44 
45       <button
46         onClick={() => {
47           mutation.mutate({
48             id: Date.now(),
49             title: 'Do Laundry',
50           })
51         }}
52       >
53         Add Todo
54       </button>
55     </div>
56   )
57 }
58 
59 render(<App />, document.getElementById('root'))

These three concepts make up most of the core functionality of React Query. The next sections of the documentation will go over each of these core concepts in great detail.