This example very briefly illustrates the 3 core concepts of React Query:
import {
useQuery,
useMutation,
useQueryClient,
QueryClient,
QueryClientProvider,
} from 'react-query'
import { getTodos, postTodo } from '../my-api'
// Create a client
const queryClient = new QueryClient()
function App() {
return (
// Provide the client to your App
<QueryClientProvider client={queryClient}>
<Todos />
</QueryClientProvider>
)
}
function Todos() {
// Access the client
const queryClient = useQueryClient()
// Queries
const query = useQuery('todos', getTodos)
// Mutations
const mutation = useMutation(postTodo, {
onSuccess: () => {
// Invalidate and refetch
queryClient.invalidateQueries('todos')
},
})
return (
<div>
<ul>
{query.data.map(todo => (
<li key={todo.id}>{todo.title}</li>
))}
</ul>
<button
onClick={() => {
mutation.mutate({
id: Date.now(),
title: 'Do Laundry',
})
}}
>
Add Todo
</button>
</div>
)
}
render(<App />, document.getElementById('root'))
import {
useQuery,
useMutation,
useQueryClient,
QueryClient,
QueryClientProvider,
} from 'react-query'
import { getTodos, postTodo } from '../my-api'
// Create a client
const queryClient = new QueryClient()
function App() {
return (
// Provide the client to your App
<QueryClientProvider client={queryClient}>
<Todos />
</QueryClientProvider>
)
}
function Todos() {
// Access the client
const queryClient = useQueryClient()
// Queries
const query = useQuery('todos', getTodos)
// Mutations
const mutation = useMutation(postTodo, {
onSuccess: () => {
// Invalidate and refetch
queryClient.invalidateQueries('todos')
},
})
return (
<div>
<ul>
{query.data.map(todo => (
<li key={todo.id}>{todo.title}</li>
))}
</ul>
<button
onClick={() => {
mutation.mutate({
id: Date.now(),
title: 'Do Laundry',
})
}}
>
Add Todo
</button>
</div>
)
}
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.