How do I cache data for state management in Nextjs and tRPC?

In scenarios where Next.js and tRPC are used together, multiple approaches can be employed for data caching and state management. The ideal approach depends on specific application requirements and use cases. Here, I'll outline several common strategies:

1. Using React Query with tRPC

React Query is a powerful library for data fetching, caching, synchronization, and updating in React applications. When used with tRPC, it can automatically manage server state.

Steps:

1. Install React Query and the tRPC client adapter:

bash
npm install @tanstack/react-query @trpc/react-query

1. Set up the tRPC client:

typescript
import { createReactQueryHooks } from '@trpc/react-query';
import { createTRPCClient } from '@trpc/client';

const trpc = createReactQueryHooks<AppRouter>();
const client = createTRPCClient<AppRouter>({ url: 'http://example.com/trpc' });

1. Use trpc.useQuery:

typescript
function MyComponent() {
  const { data, error, isLoading } = trpc.useQuery(['get-user', { id: '123' }]);

  if (isLoading) return <div>Loading...</div>;
  if (error) return <div>Error: {error.message}</div>;

  return <div>User Name: {data?.name}</div>;
}

In this example, trpc.useQuery automatically handles data extraction and caching. React Query caches data extracted by this hook and manages data updates based on your configuration, including cache duration and data refresh strategies.

2. Using SWR (Stale While Revalidate)

SWR is another popular data fetching library that provides similar functionality to React Query. It works by returning cached (stale) data while revalidating, and then re-rendering with updated data.

Steps:

1. Install SWR:

bash
npm install swr

1. Create a custom hook for tRPC:

typescript
import useSWR from 'swr';
import { createTRPCClient } from '@trpc/client';

const client = createTRPCClient<AppRouter>({ url: 'http://example.com/trpc' });

function useUserData(userId: string) {
  const fetcher = async () => {
    return client.query('get-user', { id: userId });
  };

  const { data, error } = useSWR(`get-user-${userId}`, fetcher);
  return { data, error };
}

1. Use the hook in a component:

typescript
function MyComponent({ userId }) {
  const { data, error } = useUserData(userId);

  if (!data) return <div>Loading...</div>;
  if (error) return <div>Error: {error.message}</div>;

  return <div>User Name: {data.name}</div>;
}

This approach also provides an efficient caching and data update mechanism, making data state management simple and efficient.

Summary

In the Next.js and tRPC environment, using data fetching and caching libraries like React Query or SWR can significantly simplify the complexity of state management and data synchronization. The choice of tool depends on your specific requirements and preferences, but both tools provide robust data management capabilities and support rapid application development.