# Disallow returning void from query functions

Query functions must return a value that will be cached by TanStack Query. Functions that don't return a value (void functions) can lead to unexpected behavior and might indicate a mistake in the implementation.

## Rule Details

Example of **incorrect** code for this rule:

```tsx
/* eslint "@tanstack/query/no-void-query-fn": "error" */

useQuery({
  queryKey: ['todos'],
  queryFn: async () => {
    await api.todos.fetch() // Function doesn't return the fetched data
  },
})
```

Example of **correct** code for this rule:

```tsx
/* eslint "@tanstack/query/no-void-query-fn": "error" */
useQuery({
  queryKey: ['todos'],
  queryFn: async () => {
    const todos = await api.todos.fetch()
    return todos
  },
})
```

## Attributes

- [x] ✅ Recommended
- [ ] 🔧 Fixable