How to fix useQuery() expected an object, not an array in React

What this error means

This error appears when you're using React Query (TanStack Query) with the old v3 array-based syntax instead of the modern object-based syntax that became required in v4 and beyond. In React Query v3, you could call useQuery with separate parameters: useQuery(['todos'], fetchTodos, options). Starting with v4, the API changed to accept a single object parameter containing all configuration: useQuery({ queryKey: ['todos'], queryFn: fetchTodos, ...options }). This change was made to improve API consistency, provide better TypeScript support, and make the hook more maintainable as React Query added more configuration options. If you're seeing this error, you're likely using the legacy syntax in a project that has upgraded to v4 or v5, or you're following outdated documentation or examples.

Typical symptoms

• Runtime error: "useQuery() expected an object, not an array"
• TypeScript type errors about useQuery parameter types
• useQuery hook not executing queries as expected
• Application crashes when React Query hooks are called
• Migration warnings in console after upgrading React Query versions

Common causes

1. Using React Query v4 or v5 with the deprecated v3 array-based syntax
2. Following outdated tutorials or documentation written for React Query v3
3. Upgrading React Query from v3 to v4/v5 without updating hook calls
4. Copy-pasting old code examples into a newer project
5. Mixed versions of React Query across different parts of the application

How to fix "useQuery() expected an object, not an array"

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

const { data, error, isLoading } = useQuery(
  ['todos'],
  fetchTodos,
  {
    staleTime: 5000,
    refetchOnWindowFocus: false
  }
);

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

const { data, error, isLoading } = useQuery({
  queryKey: ['todos'],
  queryFn: fetchTodos,
  staleTime: 5000,
  refetchOnWindowFocus: false
});

const { data } = useQuery(
  ['todo', todoId],
  () => fetchTodo(todoId),
  { enabled: !!todoId }
);

const { data } = useQuery({
  queryKey: ['todo', todoId],
  queryFn: () => fetchTodo(todoId),
  enabled: !!todoId
});

const results = useQueries([
  { queryKey: ['post', 1], queryFn: () => fetchPost(1) },
  { queryKey: ['post', 2], queryFn: () => fetchPost(2) }
]);

const results = useQueries({
  queries: [
    { queryKey: ['post', 1], queryFn: () => fetchPost(1) },
    { queryKey: ['post', 2], queryFn: () => fetchPost(2) }
  ]
});

// Query client defaults have changed
const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      // v4 defaults to staleTime: 0 (was undefined in v3)
      refetchOnWindowFocus: true,
      retry: 3
    }
  }
});

npm list @tanstack/react-query
# or
yarn list @tanstack/react-query

npm install @tanstack/react-query@latest
# Also update devtools if you use them
npm install @tanstack/react-query-devtools@latest

rm -rf node_modules package-lock.json
npm install

Advanced notes

Frequently asked questions

What does "useQuery() expected an object, not an array" mean?

This error appears when you're using React Query (TanStack Query) with the old v3 array-based syntax instead of the modern object-based syntax that became required in v4 and beyond. In React Query v3, you could call useQuery with separate parameters: useQuery(['todos'], fetchTodos, options). options }).

How do I fix "useQuery() expected an object, not an array"?

This error occurs when using the deprecated array syntax for React Query's useQuery hook instead of the required object syntax. React Query v4 and v5 require passing configuration as a single object parameter.

What causes "useQuery() expected an object, not an array"?

Using React Query v4 or v5 with the deprecated v3 array-based syntax Following outdated tutorials or documentation written for React Query v3 Upgrading React Query from v3 to v4/v5 without updating hook calls

Is the "useQuery() expected an object, not an array" error serious?

It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

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Official resources & further reading

• 📚React Official Documentation