useQuery()

The hooks provided by @trpc/react are a thin wrapper around React Query. For in-depth information about options and usage patterns, refer to their docs on Queries.

function useQuery(
  pathAndInput: [string, TInput?],
  opts?: UseTRPCQueryOptions;
)

The first argument is a [path, input]-tuple - if the input is optional, you can omit the , input-part.

You'll notice that you get autocompletion on the path and automatic typesafety on the input.

Example

Backend code

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

export const t = initTRPC()()

export const appRouter = t.router({
  // Create procedure at path 'hello'
  hello: t
    .procedure
    // using zod schema to validate and infer input values
    .input(
      z.object({
        text: z.string().nullish(),
      })
      .nullish() 
    )
    .query(({ input }) => {
      return {
        greeting: `hello ${input?.text ?? 'world'}`,
      };
    })
})

components/MyComponent.tsx
import { trpc } from '../utils/trpc';

export function MyComponent() {
  // input is optional, so we don't have to pass second argument
  const helloNoArgs = trpc.proxy.hello.useQuery();
  const helloWithArgs = trpc.proxy.hello.useQuery({ text: 'client' });

  return (
    <div>
      <h1>Hello World Example</h1>
      <ul>
        <li>
          helloNoArgs ({helloNoArgs.status}):{' '}
          <pre>{JSON.stringify(helloNoArgs.data, null, 2)}</pre>
        </li>
        <li>
          helloWithArgs ({helloWithArgs.status}):{' '}
          <pre>{JSON.stringify(helloWithArgs.data, null, 2)}</pre>
        </li>
      </ul>
    </div>
  );
}

Example​

Example