T
TanStack•10mo ago
skilled-lime

Suspense confusion

Given the following: 
function App() {
  return (
    <>
      <div>Header</div>
      <SuspenseComponent />
      <div>Footer</div>
    </>
  );
}

function SuspenseComponent() {
  const { data } = useSuspenseQuery({
    queryKey: ['key'],
    queryFn: async () => {
      await new Promise((res) => setTimeout(res, 5_000));
      return Math.random();
    },
  });

  return <Suspense fallback={'Loading...'}>{data}</Suspense>;
}
function App() {
  return (
    <>
      <div>Header</div>
      <SuspenseComponent />
      <div>Footer</div>
    </>
  );
}

function SuspenseComponent() {
  const { data } = useSuspenseQuery({
    queryKey: ['key'],
    queryFn: async () => {
      await new Promise((res) => setTimeout(res, 5_000));
      return Math.random();
    },
  });

  return <Suspense fallback={'Loading...'}>{data}</Suspense>;
}
I expected to initially see Header and Footer and Loading... and then after 5 seconds see the random number, but instead I get a blank screen for 5 seconds and then see everything. I have a reproduction here: https://stackblitz.com/edit/vitejs-vite-sryzjy?file=src%2FApp.tsx Am I fundamentally misunderstanding how useSuspenseQuery works?
Michael Wolfenden
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2 Replies
genetic-orange
genetic-orange•10mo ago
more like how suspense works. Suspense must be around the component that suspends. The suspending part is useQuery, so you need: 
function App() {
  return (
    <>
      <div>Header</div>
      <Suspense fallback={'Loading...'}>
        <SuspenseComponent />
      </Suspense>
      <div>Footer</div>
    </>
  );
}
function App() {
  return (
    <>
      <div>Header</div>
      <Suspense fallback={'Loading...'}>
        <SuspenseComponent />
      </Suspense>
      <div>Footer</div>
    </>
  );
}
The component istself is then de-coupled from loading states and reads just: 
function SuspenseComponent() {
  const { data } = useSuspenseQuery({
    queryKey: ['key'],
    queryFn: async () => {
      await new Promise((res) => setTimeout(res, 5_000));
      return Math.random();
    },
  });

  return <div>{data}</div>
}
function SuspenseComponent() {
  const { data } = useSuspenseQuery({
    queryKey: ['key'],
    queryFn: async () => {
      await new Promise((res) => setTimeout(res, 5_000));
      return Math.random();
    },
  });

  return <div>{data}</div>
}
skilled-lime
skilled-limeOP•10mo ago
Ahhhhhh, cheers for the speedy reply @TkDodo 🔮

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