Mutation con useMutation

Benvenuto

Nozioni di base su useMutation

import { useMutation } from '@tanstack/react-query';

const { mutate, isLoading, isError } = useMutation({
  mutationFn: (newPost) => fetch('/api/posts', {
    method: 'POST',
    body: JSON.stringify(newPost),
  }).then(r => r.json()),
});

Chiamare mutate

<button onClick={() => mutate({ title: 'New Post' })}>
  Create Post
</button>

Callback: onSuccess, onError, onSettled

useMutation({
  mutationFn: createPost,
  onSuccess: (data) => {
    console.log('Created:', data);
    navigate('/posts/' + data.id);
  },
  onError: (error) => {
    toast.error(error.message);
  },
})

Invalidare le query dopo una mutazione

import { useQueryClient } from '@tanstack/react-query';

const queryClient = useQueryClient();

const { mutate } = useMutation({
  mutationFn: createPost,
  onSuccess: () => {
    queryClient.invalidateQueries({ queryKey: ['posts'] });
  },
});

mutateAsync per la sintassi await

const { mutateAsync } = useMutation({ mutationFn: createPost });

async function handleSubmit() {
  try {
    const post = await mutateAsync({ title: 'Draft' });
    navigate('/posts/' + post.id);
  } catch (err) {
    setError(err.message);
  }
}

Disabilitare l'invio durante una mutazione

const { mutate, isPending } = useMutation({ mutationFn: saveItem });

<button onClick={() => mutate(item)} disabled={isPending}>
  {isPending ? 'Saving...' : 'Save'}
</button>

Aggiornamenti ottimistici con onMutate

useMutation({
  mutationFn: likePost,
  onMutate: async (id) => {
    await queryClient.cancelQueries({ queryKey: ['posts'] });
    const prev = queryClient.getQueryData(['posts']);
    queryClient.setQueryData(['posts'], old => old.map(p =>
      p.id === id ? { ...p, likes: p.likes + 1 } : p));
    return { prev };
  },
  onError: (err, id, ctx) => queryClient.setQueryData(['posts'], ctx.prev),
  onSettled: () => queryClient.invalidateQueries({ queryKey: ['posts'] }),
})

Reimpostare lo stato della mutazione

const { mutate, isError, reset } = useMutation({ /* ... */ });

{isError && (
  <>
    <p>Error!</p>
    <button onClick={reset}>Try Again</button>
  </>
)}

Più mutazioni in parallelo

await Promise.all([
  mutateAsync({ id: 1, title: 'First' }),
  mutateAsync({ id: 2, title: 'Second' }),
]);

Verifica rapida

Riepilogo

Prossimo argomento