undefined

undefined

// server/trpc.ts
import { initTRPC } from '@trpc/server';
import { z } from 'zod';

const t = initTRPC.create();

export const appRouter = t.router({
  hello: t.procedure
    .input(z.object({ name: z.string() }))
    .query(({ input }) => {
      return { greeting: `Hello ${input.name}` };
    }),

  createPost: t.procedure
    .input(z.object({ title: z.string(), content: z.string() }))
    .mutation(async ({ input }) => {
      // Save to database
      return { id: 1, ...input };
    }),
});

export type AppRouter = typeof appRouter;

// client/trpc.ts
import { createTRPCReact } from '@trpc/react-query';
import type { AppRouter } from '../server/trpc';

export const trpc = createTRPCReact<AppRouter>();

// Component
function MyComponent() {
  const { data } = trpc.hello.useQuery({ name: 'World' });
  const createPost = trpc.createPost.useMutation();

  return <div>{data?.greeting}</div>; // Fully typed!
}

// Server defines types
const router = t.router({
  getUser: t.procedure
    .input(z.string())
    .query(({ input }) => ({ id: input, name: 'Alice' })),
});

// Client gets automatic types
const user = await trpc.getUser.query('123');
// user is typed as { id: string, name: string }

┌─────────────┐     Type-safe     ┌──────────────┐
│   Client    │ ←────────────────→ │    Server    │
│ (React)     │   No codegen!      │   (Node.js)  │
└─────────────┘                    └──────────────┘
      ↓                                    ↓
 React Query                          tRPC Router
 (caching)                            (procedures)

import { initTRPC } from '@trpc/server';

const t = initTRPC.create();

export const appRouter = t.router({
  // Procedures go here
});

export type AppRouter = typeof appRouter;

const userRouter = t.router({
  getById: t.procedure
    .input(z.string())
    .query(({ input }) => getUser(input)),

  create: t.procedure
    .input(z.object({ name: z.string(), email: z.string() }))
    .mutation(({ input }) => createUser(input)),
});

const postRouter = t.router({
  list: t.procedure.query(() => getPosts()),
  create: t.procedure
    .input(z.object({ title: z.string() }))
    .mutation(({ input }) => createPost(input)),
});

export const appRouter = t.router({
  user: userRouter,
  post: postRouter,
});

// Client usage:
// trpc.user.getById.useQuery('123')
// trpc.post.list.useQuery()

import { adminRouter } from './admin';
import { publicRouter } from './public';

export const appRouter = t.mergeRouters(publicRouter, adminRouter);

server/
├── trpc.ts           # tRPC instance, context, middleware
├── routers/
│   ├── user.ts       # User-related procedures
│   ├── post.ts       # Post-related procedures
│   └── index.ts      # Combine all routers
└── index.ts          # Export AppRouter type

const router = t.router({
  // Simple query
  getUser: t.procedure
    .input(z.string())
    .query(({ input }) => {
      return db.user.findUnique({ where: { id: input } });
    }),

  // Query with multiple inputs
  searchUsers: t.procedure
    .input(z.object({
      query: z.string(),
      limit: z.number().default(10),
    }))
    .query(({ input }) => {
      return db.user.findMany({
        where: { name: { contains: input.query } },
        take: input.limit,
      });
    }),
});

const router = t.router({
  createUser: t.procedure
    .input(z.object({
      name: z.string().min(3),
      email: z.string().email(),
    }))
    .mutation(async ({ input }) => {
      return await db.user.create({ data: input });
    }),

  updateUser: t.procedure
    .input(z.object({
      id: z.string(),
      data: z.object({
        name: z.string().optional(),
        email: z.string().email().optional(),
      }),
    }))
    .mutation(async ({ input }) => {
      return await db.user.update({
        where: { id: input.id },
        data: input.data,
      });
    }),
});

const router = t.router({
  getUser: t.procedure
    .input(z.string())
    .output(z.object({ id: z.string(), name: z.string() })) // Optional
    .query(({ input }) => {
      return { id: input, name: 'Alice' };
    }),
});

import { z } from 'zod';

const router = t.router({
  createPost: t.procedure
    .input(z.object({
      title: z.string().min(5).max(100),
      content: z.string(),
      published: z.boolean().default(false),
      tags: z.array(z.string()).optional(),
    }))
    .mutation(({ input }) => {
      // input is fully typed and validated
      return createPost(input);
    }),
});

const createUserInput = z.object({
  email: z.string().email(),
  password: z.string().min(8),
  age: z.number().int().min(18),
  role: z.enum(['user', 'admin']),
  metadata: z.record(z.string(), z.unknown()).optional(),
});

const router = t.router({
  createUser: t.procedure
    .input(createUserInput)
    .mutation(({ input }) => {
      // All validation passed
      return saveUser(input);
    }),
});

const router = t.router({
  getUser: t.procedure
    .input(
      z.object({
        id: z.string().transform((id) => parseInt(id, 10)),
      })
    )
    .query(({ input }) => {
      // input.id is now a number
      return db.user.findUnique({ where: { id: input.id } });
    }),
});

// schemas/user.ts
export const CreateUserSchema = z.object({
  name: z.string(),
  email: z.string().email(),
});

export const UpdateUserSchema = CreateUserSchema.partial().extend({
  id: z.string(),
});

// routers/user.ts
const router = t.router({
  create: t.procedure.input(CreateUserSchema).mutation(/*...*/),
  update: t.procedure.input(UpdateUserSchema).mutation(/*...*/),
});

import { inferAsyncReturnType } from '@trpc/server';
import { CreateNextContextOptions } from '@trpc/server/adapters/next';

export async function createContext(opts: CreateNextContextOptions) {
  const session = await getSession(opts.req);

  return {
    session,
    db: prisma,
    req: opts.req,
    res: opts.res,
  };
}

export type Context = inferAsyncReturnType<typeof createContext>;

const t = initTRPC.context<Context>().create();

const router = t.router({
  getMe: t.procedure.query(({ ctx }) => {
    if (!ctx.session?.user) {
      throw new TRPCError({ code: 'UNAUTHORIZED' });
    }

    return ctx.db.user.findUnique({
      where: { id: ctx.session.user.id },
    });
  }),

  createPost: t.procedure
    .input(z.object({ title: z.string() }))
    .mutation(async ({ ctx, input }) => {
      return ctx.db.post.create({
        data: {
          title: input.title,
          authorId: ctx.session.user.id,
        },
      });
    }),
});

// ✅ Good: Lazy database connection
export async function createContext(opts: CreateNextContextOptions) {
  return {
    getDB: () => prisma, // Lazy
    session: await getSession(opts.req),
  };
}

// ❌ Bad: Heavy computation in context
export async function createContext(opts: CreateNextContextOptions) {
  const allUsers = await prisma.user.findMany(); // Too expensive!
  return { allUsers };
}

const loggerMiddleware = t.middleware(async ({ path, type, next }) => {
  const start = Date.now();
  console.log(`→ ${type} ${path}`);

  const result = await next();

  const duration = Date.now() - start;
  console.log(`✓ ${type} ${path} - ${duration}ms`);

  return result;
});

const loggedProcedure = t.procedure.use(loggerMiddleware);

const isAuthed = t.middleware(({ ctx, next }) => {
  if (!ctx.session?.user) {
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }

  return next({
    ctx: {
      ...ctx,
      user: ctx.session.user, // Narrow type
    },
  });
});

// Protected procedure builder
const protectedProcedure = t.procedure.use(isAuthed);

const router = t.router({
  // Public
  getPublicPosts: t.procedure.query(() => getPosts()),

  // Protected - requires authentication
  getMyPosts: protectedProcedure.query(({ ctx }) => {
    // ctx.user is guaranteed to exist
    return getPostsByUser(ctx.user.id);
  }),
});

const timingMiddleware = t.middleware(async ({ next }) => {
  const start = performance.now();
  const result = await next();
  console.log(`Execution time: ${performance.now() - start}ms`);
  return result;
});

const rateLimitMiddleware = t.middleware(async ({ ctx, next }) => {
  await checkRateLimit(ctx.session?.user?.id);
  return next();
});

const protectedProcedure = t.procedure
  .use(timingMiddleware)
  .use(rateLimitMiddleware)
  .use(isAuthed);

const enrichContextMiddleware = t.middleware(async ({ ctx, next }) => {
  const user = ctx.session?.user
    ? await ctx.db.user.findUnique({ where: { id: ctx.session.user.id } })
    : null;

  return next({
    ctx: {
      ...ctx,
      user, // Full user object
    },
  });
});

import { TRPCError } from '@trpc/server';

const router = t.router({
  getUser: t.procedure
    .input(z.string())
    .query(async ({ input }) => {
      const user = await db.user.findUnique({ where: { id: input } });

      if (!user) {
        throw new TRPCError({
          code: 'NOT_FOUND',
          message: `User ${input} not found`,
        });
      }

      return user;
    }),
});

const router = t.router({
  deleteUser: t.procedure
    .input(z.string())
    .mutation(async ({ input, ctx }) => {
      try {
        return await ctx.db.user.delete({ where: { id: input } });
      } catch (error) {
        if (error.code === 'P2025') { // Prisma not found
          throw new TRPCError({
            code: 'NOT_FOUND',
            message: 'User not found',
            cause: error,
          });
        }
        throw new TRPCError({
          code: 'INTERNAL_SERVER_ERROR',
          message: 'Failed to delete user',
          cause: error,
        });
      }
    }),
});

const t = initTRPC.context<Context>().create({
  errorFormatter({ shape, error }) {
    return {
      ...shape,
      data: {
        ...shape.data,
        zodError:
          error.code === 'BAD_REQUEST' && error.cause instanceof ZodError
            ? error.cause.flatten()
            : null,
      },
    };
  },
});