# nextjs-state-management Implementation Examples

## Inline Examples

```tsx
'use client';
import { useSearchParams, useRouter } from 'next/navigation';

function SearchFilter() {
  const searchParams = useSearchParams();
  const router = useRouter();

  function updateQuery(term: string) {
    const params = new URLSearchParams(searchParams.toString());
    params.set('q', term);
    router.replace(`?${params.toString()}`);
  }
  return <input onChange={(e) => updateQuery(e.target.value)} />;
}
```

```tsx
// Automated caching, deduplication, and revalidation
const { data, error } = useSWR('/api/user', fetcher, {
  refreshInterval: 30000,
});
```

```tsx
// store.ts — minimal Zustand store
import { create } from 'zustand';
export const useCartStore = create<CartState>()((set) => ({
  items: [],
  addItem: (item) => set((s) => ({ items: [...s.items, item] })),
}));
```
