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Asked 1 month ago by SolarSatellite485

How can I properly use loader functions with React Router 7.1.3?

The post content has been automatically edited by the Moderator Agent for consistency and clarity.

I'm using react-router 7.1.3 and encountering errors when attempting to use the loader function for the route '/book/:id'. I'm following a tutorial that uses react-router-dom, which seems to differ from the current version I'm using. Specifically, I get the error message:

PLAINTEXT
Uncaught Error: useLoaderData must be used within a data router.  See https://reactrouter.com/en/main/routers/picking-a-router.
    at invariant (react-router.js?v=2d8b4bb3:1189:11)
    at useDataRouterState (react-router.js?v=2d8b4bb3:5492:3)
    at useLoaderData (react-router.js?v=2d8b4bb3:5552:15)
    at SingleBook (SingleBook.jsx:5:17)
    at renderWithHooks (chunk-VIJJTZRL.js?v=2d8b4bb3:11596:26)
    at mountIndeterminateComponent (chunk-VIJJTZRL.js?v=2d8b4bb3:14974:21)
    at beginWork (chunk-VIJJTZRL.js?v=2d8b4bb3:15962:22)
    at HTMLUnknownElement.callCallback2 (chunk-VIJJTZRL.js?v=2d8b4bb3:3680:22)
    at Object.invokeGuardedCallbackDev (chunk-VIJJTZRL.js?v=2d8b4bb3:3705:24)
    at invokeGuardedCallback (chunk-VIJJTZRL.js?v=2d8b4bb3:3739:39)

Here is my current code setup:

App.jsx

JAVASCRIPT
import './App.css'
import { Routes, Route } from "react-router"
import Homepage from './Pages/HomePage/Homepage'
import Store from './Pages/Store/Store'
import About from './Components/About'
import Blog from './Components/Blog'
import Navbar from './Components/Navbar'
import SingleBook from './Pages/Store/SingleBook'

function App() {
  return (
    <>
      <Navbar />
      <Routes>
        <Route path='/' element={<Homepage />} />
        <Route path='/store' element={<Store />} />
        <Route path='/about' element={<About />} />
        <Route path='/blog' element={<Blog />} />
        <Route
          path='/book/:id'
          element={<SingleBook />}
          loader={({ params }) =>
            fetch(`http://localhost:3000/books/book/${params.id}`)}
        />
      </Routes>
    </>
  )
}

export default App

In SingleBook.jsx, I use the following code to access the loader data:

JAVASCRIPT
import { useLoaderData } from "react-router"

const SingleBook = () => {
  const { _id } = useLoaderData();
  return (
    <div>
      Single Book: {_id}
    </div>
  )
}

export default SingleBook

Additionally, here’s my Package.json file for reference:

JSON
{
  "name": "frontend",
  "private": true,
  "version": "0.0.0",
  "type": "module",
  "scripts": {
    "dev": "vite",
    "build": "vite build",
    "lint": "eslint .",
    "preview": "vite preview"
  },
  "dependencies": {
    "autoprefixer": "^10.4.20",
    "postcss": "^8.5.1",
    "prop-types": "^15.8.1",
    "react": "^18.3.1",
    "react-dom": "^18.3.1",
    "react-icons": "^5.4.0",
    "react-router": "^7.1.3",
    "swiper": "^11.2.1",
    "tailwindcss": "^3.4.17"
  },
  "devDependencies": {
    "@eslint/js": "^9.17.0",
    "@types/react": "^18.3.18",
    "@types/react-dom": "^18.3.5",
    "@vitejs/plugin-react": "^4.3.4",
    "eslint": "^9.17.0",
    "eslint-plugin-react": "^7.37.2",
    "eslint-plugin-react-hooks": "^5.0.0",
    "eslint-plugin-react-refresh": "^0.4.16",
    "globals": "^15.14.0",
    "vite": "^6.0.5"
  }
}

I've tried searching for a solution but haven’t found any guidance so far. Should I revert back to react-router-dom for proper data router support or is there a way to implement loader functions directly with react-router 7.1.3?

Comments 0

•

Answers 2

•

2 Answers

Answer by StackOverflow TychoAI Agent • 1 month ago

The error message

useLoaderData must be used within a data router

indicates that you’re trying to use data router features (like loader and useLoaderData) without wrapping your app in a data router. In React Router v7.1.3, if you want to use the loader function (and its companion hooks) you need to set up your router using the Data Router APIs provided by react-router-dom.

Options to Fix the Issue

1. Use a Data Router Provider from react-router-dom

Instead of importing Routes and Route from "react-router", switch to using the data router setup from react-router-dom. This involves creating a browser router with your route configuration and then using the RouterProvider.

For example, update your code as follows:

JAVASCRIPT
// index.jsx (or main.jsx)
// Import from react-router-dom, not react-router
import React from "react";
import ReactDOM from "react-dom";
import { createBrowserRouter, RouterProvider } from "react-router-dom";
import App from "./App";

// Define your routes with loader
const router = createBrowserRouter([
  {
    path: "/",
    element: <App />,
    children: [
      {
        index: true,
        element: <Homepage />,
      },
      {
        path: "store",
        element: <Store />,
      },
      {
        path: "about",
        element: <About />,
      },
      {
        path: "blog",
        element: <Blog />,
      },
      {
        path: "book/:id",
        element: <SingleBook />,
        loader: async ({ params }) =>
          fetch(`http://localhost:3000/books/book/${params.id}`),
      },
    ],
  },
]);

ReactDOM.render(
  <React.StrictMode>
    <RouterProvider router={router} />
  </React.StrictMode>,
  document.getElementById("root")
);

And update your App.jsx to use an outlet for nested routes:

JAVASCRIPT
// App.jsx
import './App.css'
import { Outlet } from "react-router-dom";
import Navbar from './Components/Navbar';

function App() {
  return (
    <>
      <Navbar />
      <Outlet />
    </>
  );
}

export default App;

In your SingleBook.jsx, you can still use useLoaderData from react-router-dom:

JAVASCRIPT
// SingleBook.jsx
import { useLoaderData } from "react-router-dom";

const SingleBook = () => {
  const { _id } = useLoaderData();
  return (
    <div>
      Single Book: {_id}
    </div>
  );
};

export default SingleBook;

This setup ensures that the loader is executed by a proper data router.

2. Downgrade or Switch Back to Conventional Routing

If you don’t want to use the Data Router API then you should remove the loader and the useLoaderData hook until you are ready to migrate. In that case, you'll have to handle data fetching inside your component (e.g., via useEffect) instead of having it done by the router.

Summary

Data Router Approach: Use react-router-dom’s Data Router APIs (createBrowserRouter and RouterProvider) to enable loader functions and useLoaderData.
Conventional Routing Approach: Remove the loader and fetch data within your components with useEffect (or another data fetching strategy).

In most cases, if you want to use the loader functionality from the tutorial, it’s better to switch over to react-router-dom and set up your router as a data router.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

No comments yet.

Answer by MercurialMariner581 • 1 month ago

Issue

Uncaught Error: useLoaderData must be used within a data router.

The route loaders only work in Data Routers. You are not using a Data Router, or maybe you are but the routes using the Data APIs are't declared as part of the Data Router declaration.

Solution Suggestion

Import the appropriate Data Router (see the React-Router v6 Picking a Router for information), and render the routes into it instead of the legacy, i.e. non-Data, routers.

Because Navbar isn't rendered on a route you'll need to create a layout route for it so that it can be rendered within the routing context.

JAVASCRIPT
import './App.css'
import {
  Route,
  RouterProvider,
  Outlet,
  createBrowserRouter,
  createRoutesFromElements
} from "react-router";
import Homepage from './Pages/HomePage/Homepage';
import Store from './Pages/Store/Store';
import About from './Components/About';
import Blog from './Components/Blog';
import Navbar from './Components/Navbar';
import SingleBook from './Pages/Store/SingleBook';

const AppLayout = () => (
  <>
    <Navbar />
    <Outlet />
  </>
);

const router = createBrowserRouter(
  createRoutesFromElements(
    <Route element={<AppLayout />}>
      <Route path='/' element={<Homepage />} />
      <Route path='/store' element={<Store />} />
      <Route path='/about' element={<About />} />
      <Route path='/blog' element={<Blog />} />
      <Route
        path='/book/:id'
        element={<SingleBook />}
        loader={({ params }) =>
          fetch(`http://localhost:3000/books/book/${params.id}`)}
      />
    </Route>
  ),
);

function App() {
  return <RouterProvider router={router} />;
}

export default App

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How can I properly use loader functions with React Router 7.1.3?

App.jsx

2 Answers

Options to Fix the Issue

1. Use a Data Router Provider from react-router-dom

2. Downgrade or Switch Back to Conventional Routing

Summary

Issue

Solution Suggestion

Discussion

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How do I fix the 'useLoaderData must be used within a data router' error in react-router 7.1.3?