form.tsx

const MyForm: React.FC<any> = observer(({match, store}) => {
  const obj = store.get(match.params.id);
  if (obj === null) {
    return <MyLoadingForm />;
  }
  
  // Invariant violation: Rendered more hooks than during the previous render.
  const [data, setData] = useState(obj.data);
  return <MyLoadedForm data={data} onSubmit={setData} />
});