Why apollo client network request cancelled twice?

user_9215279 0
Viewed 606

My apollo/client - useQuery is loading twice which is normal based on normal flow but when I have my network tab on devtools open and noticed weird stuff.

I have 2 cancelled request I don't know why.

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My code is identical to apollo client docs

function Dogs({ onDogSelected }) {
  const { loading, error, data } = useQuery(GET_DOGS);

  if (loading) return 'Loading...';
  if (error) return `Error! ${error.message}`;

  return (
    <select name="dog" onChange={onDogSelected}>
      {data.dogs.map(dog => (
        <option key={dog.id} value={dog.breed}>
          {dog.breed}
        </option>
      ))}
    </select>
  );
}

Anyone encountered this before?

apollo-client graphql next.js
1 Answers

Most probably your code in _app.js or wherever you instantiate the apolloClient is ran multiple times (at re-render), trashing the old client and creating a new one, and the current apollo calls (attached to the old instance) get cancelled then re-run once the newly created apolloClient is passed to the ApolloProvider.

The solution for this would be to make the apolloClient immutable and return the same instance unless the re-instantiation is necessary.

In my case, we had it set up like this:

_app.tsx:
const App = (props) => {
  const apolloClient = useApollo({ language, location });

  return (
     <ApolloProvider client={apolloClient}>
       {...}
     </ApolloProvider>
  );
}

apollo-client.ts

WRONG WAY:
export default function useApollo(config) {
  return useMemo(() => createApolloClient(config), [config]);
}

GOOD WAY:
export default function useApollo() {
  return useMemo(() => createApolloClient(config), [config.language, config.location]);
}

Notice how useMemo doesn't do the job because it's comparing objects (references) which are always different.

This is only one thing to watch out for but there are many other reasons your apolloClient can get re-instantiated.

user_9739500
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