In the ever-evolving landscape of web development, TypeScript has emerged as a beacon of hope for developers aiming to bring strong typing and enhanced error-checking to their JavaScript applications. Among its many uses, TypeScript shines brightly in the realm of API development, where type safety is not just a convenience but a necessity for reliable, scalable software. This blog post explores the integration of TypeScript with tRPC, an end-to-end typesafe API framework, to provide a comprehensive guide to building type-safe APIs.

Understanding tRPC and Its Fit with TypeScript

tRPC stands for TypeScript RPC and is designed to provide a seamless development experience by eliminating the traditional API layer. Instead of writing API fetch calls and handlers separately, tRPC allows developers to call server-side functions directly from the client as if they were local functions, with all the type safety preserved from end to end.

The combination of TypeScript and tRPC creates a powerful duo that can significantly reduce the runtime errors and improve the developer experience by providing autocomplete and type checking at compile time.

Setting Up a TypeScript + tRPC Environment

To begin, you’ll need a Node.js environment. You can set up a new project using npm or yarn. Here's how you can set up a basic tRPC application:

1. Initialize a new node project:

mkdir my-trpc-app

cd my-trpc-app

npm init -y

npm install typescript ts-node @trpc/server @trpc/client react react-dom next

2. Set up TypeScript:

npx tsc --init

Modify the generated tsconfig.json to suit your project needs, ensuring that the compiler options are set for React if you're planning to use it on the client side.

3. Create a basic tRPC server:

import * as trpc from '@trpc/server';

import { z } from 'zod';


const appRouter = trpc.router().query('getHello', {

input: z .object({

name: z.string().optional(), }) .optional(),

resolve({ input }) {

return {

greeting: `Hello ${input?.name ?? 'world'}`, }; }, });


export type AppRouter = typeof appRouter;

In this simple server setup, we define a single query getHello which optionally takes a name and returns a greeting message.

4. Set up the tRPC client in a Next.js application:

import { createReactQueryHooks } from '@trpc/react';

import type { AppRouter } from './server/trpc';


const trpc = createReactQueryHooks<AppRouter>();

export default trpc;

This code snippet sets up the tRPC client hooks that can be used within React components to call the API directly.

Real-World Usage and Best Practices

Using tRPC and TypeScript in a real-world scenario involves careful structuring of your types and API calls to ensure maximum efficiency and error handling capabilities. Here are some insights and best practices from real-world usage:

• Strongly Type Everything: The power of TypeScript comes from its type system. Use it to define the shape of every piece of data in your application.
• Error Handling: tRPC provides built-in error handling mechanisms. Use them to handle and propagate errors from your server to your client in a type-safe manner.
• Performance Considerations: While tRPC eliminates the need for writing API schemas and fetch hooks, it's important to monitor the performance in large applications and optimize the data loading strategies.

Example: Type-Safe Error Handling

Handling errors in a type-safe way is crucial for maintaining the reliability of your application. Here’s how you can handle errors in tRPC:

appRouter.query('getHello', {

input: z.string().optional(),

resolve({ input }) {

try { // Potentially failing operation } catch (error) {

throw new trpc.TRPCError({

code: 'INTERNAL_SERVER_ERROR',

message: 'An error occurred', }); } }, });

Conclusion

The integration of TypeScript with tRPC provides a robust framework for building type-safe APIs that are efficient and easy to maintain. By leveraging the type system of TypeScript throughout your stack, you can significantly reduce bugs and improve the development process. As TypeScript continues to evolve, tools like tRPC are pivotal in harnessing the full potential of type-safe programming in JavaScript environments.