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useParams in React Router: Complete Guide (2026)

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useParams Explained: React Router URL Parameter Extraction Guide

Master React Router's useParams hook. Learn URL parameter extraction, TypeScript typing, nested routes, and real-world patterns for dynamic routing with production examples.

Table of Contents

# useParams in React Router: Complete Guide (2026)

Dynamic routing is essential for modern web applications. Whether you're building a product catalog, user profiles, or blog posts, you need to extract values from the URL and pass them to your components. React Router's useParams hook is your primary tool for this task. This comprehensive guide shows you exactly how to use it correctly, avoid common pitfalls, and implement production-ready routing patterns.

# Table of Contents

  1. Understanding URL Parameters
  2. Basic useParams Usage
  3. TypeScript with useParams
  4. Multiple Route Parameters
  5. useParams vs useSearchParams vs useLocation
  6. Common Mistakes and Solutions
  7. Real-World Implementation Patterns
  8. Advanced Techniques
  9. FAQ

# Understanding URL Parameters

Before using useParams, you need to understand what URL parameters are and how they differ from other ways to pass data.

# Types of URL Data

URLs can carry data in multiple ways:

typescript 
https://example.com/products/42/reviews?page=1&sort=recent#comments
                       └──┬──┘  └─┬─┘  └────┬────────┬────────┘  └───┬──┘
                          │      │         │        │             │
                    Path Segments │    Search Parameters (Query)   Fragment
                          │       │
                    Route Parameters (URL Params)

Route Parameters (/products/42):

  • Part of the path structure
  • Required for the route to match
  • Extracted with useParams()
  • Example: /users/:id, /posts/:postId/comments/:commentId

Search Parameters (?page=1&sort=recent):

  • Query string at the end of the URL
  • Optional, don't affect route matching
  • Extracted with useSearchParams()
  • Example: filtering, pagination, sorting

Fragment (#comments):

  • Hash at the very end
  • Client-side navigation only
  • Accessed via window.location.hash

This guide focuses on route parameters and useParams().

# Basic useParams Usage

# Defining Routes with Parameters

First, you define routes with parameter placeholders in your route configuration:

typescript 
// routes.ts or main.tsx
import { createBrowserRouter } from 'react-router-dom';
import ProductPage from './pages/ProductPage';
import UserProfile from './pages/UserProfile';
import PostDetail from './pages/PostDetail';

export const router = createBrowserRouter([
  {
    path: '/',
    element: <App />,
    children: [
      // Single parameter
      { 
        path: '/products/:id', 
        element: <ProductPage /> 
      },
      
      // Multiple parameters
      { 
        path: '/users/:userId', 
        element: <UserProfile /> 
      },
      
      // Nested parameters
      { 
        path: '/posts/:postId/comments/:commentId', 
        element: <PostDetail /> 
      },
    ],
  },
]);

The colon (:) prefix indicates a dynamic segment that captures URL values.

# Extracting Parameters in Components

TypeScript Version

typescript 
import { useParams } from 'react-router-dom';

function ProductPage() {
  // useParams returns an object with all route parameters
  // ⚠️ Values are ALWAYS strings, even if they look like numbers
  const params = useParams();
  
  // params = { id: "42" } when URL is /products/42
  const productId = params.id; // "42" (string)
  
  // Convert to number if needed
  const id = productId ? parseInt(productId, 10) : null;
  
  if (!id) {
    return <div>Invalid product ID</div>;
  }

  return (
    <div>
      <h1>Product {id}</h1>
      <p>Loading product details...</p>
    </div>
  );
}

JavaScript Version

javascript 
import { useParams } from 'react-router-dom';

function ProductPage() {
  const params = useParams();
  const productId = params.id; // "42" (string)
  const id = productId ? parseInt(productId, 10) : null;

  if (!id) {
    return <div>Invalid product ID</div>;
  }

  return (
    <div>
      <h1>Product {id}</h1>
      <p>Loading product details...</p>
    </div>
  );
}

# TypeScript with useParams

TypeScript support is crucial for safe parameter handling. React Router's useParams is generic, allowing you to define the exact shape of parameters.

# Proper TypeScript Usage

TypeScript Version

typescript 
import { useParams } from 'react-router-dom';
import { ReactNode } from 'react';

// Define parameter types
interface ProductParams {
  id: string;
}

function ProductPage() {
  // Pass interface as generic argument
  // TypeScript now knows params has an 'id' property
  const params = useParams<ProductParams>();
  
  // TypeScript knows this is safe
  const productId = params.id;
  
  // This would error: Property 'name' does not exist on type 'ProductParams'
  // const name = params.name; ❌ TypeScript error
  
  return <div>Product: {productId}</div>;
}

// Multiple parameters
interface CustomerTaskParams {
  customerId: string;
  taskId: string;
}

function CustomerTaskDetail() {
  const params = useParams<CustomerTaskParams>();
  
  // Both properties are typed and autocompleted
  return (
    <div>
      <h1>Customer {params.customerId}</h1>
      <p>Task {params.taskId}</p>
    </div>
  );
}

# Creating Reusable Parameter Types

For larger applications, create a centralized parameter type file:

typescript 
// types/params.ts
export interface ProductPageParams {
  id: string;
}

export interface UserProfileParams {
  userId: string;
}

export interface PostDetailParams {
  postId: string;
  commentId: string;
}

export interface CategoryListParams {
  category: string;
}

// pages/ProductPage.tsx
import { useParams } from 'react-router-dom';
import type { ProductPageParams } from '../types/params';

function ProductPage() {
  const { id } = useParams<ProductPageParams>();
  // TypeScript provides full type checking
  return <div>Product: {id}</div>;
}

# Type-Safe Parameter Validation

Always validate parameters, as they come from the URL (user-controlled):

typescript 
import { useParams } from 'react-router-dom';
import { useEffect, useState } from 'react';

interface ProductParams {
  id: string;
}

interface Product {
  id: number;
  name: string;
  price: number;
}

function ProductPage() {
  const params = useParams<ProductParams>();
  const [product, setProduct] = useState<Product | null>(null);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    // Validate that ID exists and is numeric
    if (!params.id) {
      setError('Product ID is required');
      return;
    }

    const productId = parseInt(params.id, 10);
    
    if (isNaN(productId)) {
      setError('Product ID must be a number');
      return;
    }

    if (productId <= 0) {
      setError('Product ID must be positive');
      return;
    }

    // Now safely fetch the product
    fetchProduct(productId);
  }, [params.id]);

  const fetchProduct = async (id: number) => {
    try {
      const response = await fetch(`/api/products/${id}`);
      if (!response.ok) throw new Error('Product not found');
      const data = await response.json();
      setProduct(data);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Failed to load product');
      setProduct(null);
    }
  };

  if (error) return <div className="error">{error}</div>;
  if (!product) return <div>Loading...</div>;

  return (
    <div>
      <h1>{product.name}</h1>
      <p>${product.price}</p>
    </div>
  );
}

# Multiple Route Parameters

Many real-world routes require multiple parameters. Understanding how to handle them correctly is essential.

# Defining Routes with Multiple Parameters

typescript 
// Route definition
{
  path: '/users/:userId/posts/:postId/comments/:commentId',
  element: <CommentDetail />
}

// URL examples that would match:
// /users/123/posts/456/comments/789
// /users/alice/posts/post-001/comments/comment-001

# Extracting Multiple Parameters

TypeScript Version

typescript 
import { useParams } from 'react-router-dom';

interface CommentDetailParams {
  userId: string;
  postId: string;
  commentId: string;
}

function CommentDetail() {
  const { userId, postId, commentId } = useParams<CommentDetailParams>();
  
  // All three parameters are available and typed
  console.log('User:', userId, 'Post:', postId, 'Comment:', commentId);

  return (
    <div>
      <h2>User {userId}</h2>
      <article>Post {postId}</article>
      <div className="comment">Comment {commentId}</div>
    </div>
  );
}

JavaScript Version

javascript 
import { useParams } from 'react-router-dom';

function CommentDetail() {
  const { userId, postId, commentId } = useParams();
  
  return (
    <div>
      <h2>User {userId}</h2>
      <article>Post {postId}</article>
      <div className="comment">Comment {commentId}</div>
    </div>
  );
}

# Important: Parameters Must Match Route Definition

This is a common source of bugs:

typescript 
// ❌ MISMATCH: Route uses :id but code accesses :productId
// Route definition
{ path: '/products/:id', element: <ProductPage /> }

// Component
function ProductPage() {
  const { productId } = useParams(); // undefined! Parameter is called :id
  const { id } = useParams(); // ✅ Correct
}

// ✅ CORRECT: Names must match exactly
{ path: '/products/:productId', element: <ProductPage /> }

function ProductPage() {
  const { productId } = useParams(); // ✅ Now correct
}

# useParams vs useSearchParams vs useLocation

React Router provides three hooks for accessing URL data. Understanding the differences is crucial:

Hook Purpose Use Case Example
useParams Route parameters (path) Dynamic resource IDs /users/:id → { id: "123" }
useSearchParams Query string parameters Filtering, sorting, pagination ?page=1&sort=date
useLocation Full URL information Advanced routing logic Whole location object

# useParams - Dynamic Route Values

typescript 
// Route: /products/:id
// URL: /products/42
// useParams returns: { id: "42" }

const { id } = useParams<{ id: string }>();

# useSearchParams - Query Strings

typescript 
import { useSearchParams } from 'react-router-dom';

function SearchResults() {
  // URL: /search?query=react&category=hooks&page=2
  const [searchParams, setSearchParams] = useSearchParams();
  
  const query = searchParams.get('query'); // "react"
  const category = searchParams.get('category'); // "hooks"
  const page = searchParams.get('page'); // "2"
  
  // Update search params
  const handleSort = (field: string) => {
    searchParams.set('sort', field);
    setSearchParams(searchParams);
  };

  return (
    <div>
      <h1>Results for: {query}</h1>
      <button onClick={() => handleSort('date')}>Sort by Date</button>
      <button onClick={() => handleSort('popularity')}>Sort by Popularity</button>
    </div>
  );
}

# useLocation - Full URL Information

typescript 
import { useLocation } from 'react-router-dom';

function PageTracker() {
  const location = useLocation();
  
  // location object contains:
  // {
  //   pathname: "/products/42",
  //   search: "?page=1&sort=date",
  //   hash: "#reviews",
  //   key: "default",
  //   state: undefined
  // }
  
  return (
    <div>
      <p>Current path: {location.pathname}</p>
      <p>Query string: {location.search}</p>
    </div>
  );
}

# Common Mistakes and Solutions

# Mistake 1: Forgetting Parameters Are Always Strings

typescript 
// ❌ WRONG: Treating parameter as number without conversion
const { userId } = useParams<{ userId: string }>();
if (userId > 10) {  // String comparison!
  // This compares strings alphabetically, not numerically
}

// ✅ CORRECT: Convert to number first
const id = parseInt(userId, 10);
if (id > 10) {
  // Now correct numeric comparison
}

# Mistake 2: Parameter Name Mismatch

typescript 
// Route definition
{ path: '/products/:productId', element: <ProductPage /> }

// ❌ WRONG
const { id } = useParams(); // undefined

// ✅ CORRECT
const { productId } = useParams(); // works

# Mistake 3: Not Handling Missing Parameters

typescript 
// ❌ WRONG: Assumes parameter always exists
function UserPage() {
  const { userId } = useParams<{ userId: string }>();
  // If route is /users and :userId is missing, this crashes
  return <div>{userId.toUpperCase()}</div>;
}

// ✅ CORRECT: Validate parameter exists
function UserPage() {
  const { userId } = useParams<{ userId: string }>();
  
  if (!userId) {
    return <div>User ID is required</div>;
  }
  
  return <div>{userId.toUpperCase()}</div>;
}

# Mistake 4: Recreating Objects in Dependency Arrays

typescript 
// ❌ PROBLEMATIC: New params object on every render
function ProductPage() {
  const params = useParams();
  
  useEffect(() => {
    loadProduct(params.id);
  }, [params]); // params object is different every render!
}

// ✅ CORRECT: Use specific values as dependencies
function ProductPage() {
  const { id } = useParams<{ id: string }>();
  
  useEffect(() => {
    loadProduct(id);
  }, [id]); // Only re-run if id changes
}

# Real-World Implementation Patterns

# Pattern 1: Product Detail Page with Data Loading

TypeScript Version

typescript 
import { useParams, useNavigate } from 'react-router-dom';
import { useEffect, useState } from 'react';

interface ProductParams {
  id: string;
}

interface Product {
  id: number;
  name: string;
  description: string;
  price: number;
  image: string;
  inStock: boolean;
}

function ProductDetail() {
  const navigate = useNavigate();
  const { id } = useParams<ProductParams>();
  
  const [product, setProduct] = useState<Product | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    if (!id || isNaN(parseInt(id))) {
      setError('Invalid product ID');
      setLoading(false);
      return;
    }

    const fetchProduct = async () => {
      try {
        setLoading(true);
        const response = await fetch(`/api/products/${id}`);
        
        if (response.status === 404) {
          setError('Product not found');
          return;
        }
        
        if (!response.ok) {
          throw new Error('Failed to load product');
        }
        
        const data = await response.json();
        setProduct(data);
        setError(null);
      } catch (err) {
        setError(err instanceof Error ? err.message : 'Unknown error');
      } finally {
        setLoading(false);
      }
    };

    fetchProduct();
  }, [id]);

  if (loading) {
    return <div className="spinner">Loading...</div>;
  }

  if (error) {
    return (
      <div className="error">
        <p>{error}</p>
        <button onClick={() => navigate('/products')}>
          Back to Products
        </button>
      </div>
    );
  }

  if (!product) {
    return <div>No product found</div>;
  }

  return (
    <div className="product-detail">
      <button onClick={() => navigate(-1)}>← Back</button>
      
      <img src={product.image} alt={product.name} />
      
      <h1>{product.name}</h1>
      <p className="description">{product.description}</p>
      <p className="price">${product.price}</p>
      
      <button disabled={!product.inStock}>
        {product.inStock ? 'Add to Cart' : 'Out of Stock'}
      </button>
    </div>
  );
}

export default ProductDetail;

JavaScript Version

javascript 
import { useParams, useNavigate } from 'react-router-dom';
import { useEffect, useState } from 'react';

function ProductDetail() {
  const navigate = useNavigate();
  const { id } = useParams();
  
  const [product, setProduct] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    if (!id || isNaN(parseInt(id))) {
      setError('Invalid product ID');
      setLoading(false);
      return;
    }

    const fetchProduct = async () => {
      try {
        setLoading(true);
        const response = await fetch(`/api/products/${id}`);
        
        if (response.status === 404) {
          setError('Product not found');
          return;
        }
        
        if (!response.ok) {
          throw new Error('Failed to load product');
        }
        
        const data = await response.json();
        setProduct(data);
        setError(null);
      } catch (err) {
        setError(err.message || 'Unknown error');
      } finally {
        setLoading(false);
      }
    };

    fetchProduct();
  }, [id]);

  if (loading) return <div className="spinner">Loading...</div>;
  if (error) return <div className="error">{error}</div>;
  if (!product) return <div>No product found</div>;

  return (
    <div className="product-detail">
      <button onClick={() => navigate(-1)}>← Back</button>
      <img src={product.image} alt={product.name} />
      <h1>{product.name}</h1>
      <p>{product.description}</p>
      <p>${product.price}</p>
      <button disabled={!product.inStock}>
        {product.inStock ? 'Add to Cart' : 'Out of Stock'}
      </button>
    </div>
  );
}

export default ProductDetail;

# Pattern 2: Nested Route Parameters (User → Post → Comment)

TypeScript Version

typescript 
import { useParams, Link } from 'react-router-dom';
import { useEffect, useState } from 'react';

interface CommentParams {
  userId: string;
  postId: string;
  commentId: string;
}

interface Comment {
  id: number;
  author: string;
  text: string;
  createdAt: string;
}

function CommentPage() {
  const { userId, postId, commentId } = useParams<CommentParams>();
  const [comment, setComment] = useState<Comment | null>(null);

  useEffect(() => {
    // Validate all parameters exist
    if (!userId || !postId || !commentId) {
      return;
    }

    const loadComment = async () => {
      const response = await fetch(
        `/api/users/${userId}/posts/${postId}/comments/${commentId}`
      );
      const data = await response.json();
      setComment(data);
    };

    loadComment();
  }, [userId, postId, commentId]);

  if (!comment) return <div>Loading...</div>;

  return (
    <div>
      {/* Navigate with parameters */}
      <Link to={`/users/${userId}/posts/${postId}`}>
        ← Back to Post
      </Link>
      
      <h3>{comment.author}</h3>
      <p>{comment.text}</p>
      <time>{comment.createdAt}</time>
    </div>
  );
}

# Pattern 3: Search and Filter with Parameters

Real-world applications often combine route parameters with search functionality:

TypeScript Version

typescript 
import { useParams, useSearchParams, Link } from 'react-router-dom';
import { useEffect, useState } from 'react';

interface CategoryParams {
  categoryId: string;
}

interface Product {
  id: number;
  name: string;
  price: number;
}

function CategoryPage() {
  const { categoryId } = useParams<CategoryParams>();
  const [searchParams, setSearchParams] = useSearchParams();
  
  const [products, setProducts] = useState<Product[]>([]);
  const [loading, setLoading] = useState(true);

  // Get search and sort from query params
  const searchTerm = searchParams.get('search') || '';
  const sortBy = searchParams.get('sort') || 'name';

  useEffect(() => {
    if (!categoryId) return;

    const loadProducts = async () => {
      const params = new URLSearchParams({
        category: categoryId,
        search: searchTerm,
        sort: sortBy,
      });

      const response = await fetch(`/api/products?${params}`);
      const data = await response.json();
      setProducts(data);
      setLoading(false);
    };

    loadProducts();
  }, [categoryId, searchTerm, sortBy]);

  const handleSearch = (term: string) => {
    searchParams.set('search', term);
    setSearchParams(searchParams);
  };

  const handleSort = (field: string) => {
    searchParams.set('sort', field);
    setSearchParams(searchParams);
  };

  if (loading) return <div>Loading...</div>;

  return (
    <div>
      <h1>Category {categoryId}</h1>
      
      <input
        type="text"
        placeholder="Search products..."
        value={searchTerm}
        onChange={(e) => handleSearch(e.target.value)}
      />

      <select value={sortBy} onChange={(e) => handleSort(e.target.value)}>
        <option value="name">Sort by Name</option>
        <option value="price">Sort by Price</option>
        <option value="newest">Sort by Newest</option>
      </select>

      <div className="products">
        {products.map((product) => (
          <Link key={product.id} to={`/products/${product.id}`}>
            <h3>{product.name}</h3>
            <p>${product.price}</p>
          </Link>
        ))}
      </div>
    </div>
  );
}

# Testing with useParams

Testing components that use useParams requires mocking the router:

typescript 
import { render, screen } from '@testing-library/react';
import { MemoryRouter, Routes, Route } from 'react-router-dom';
import ProductDetail from './ProductDetail';

describe('ProductDetail', () => {
  it('renders product with correct ID from URL', () => {
    render(
      <MemoryRouter initialEntries={['/products/42']}>
        <Routes>
          <Route path="/products/:id" element={<ProductDetail />} />
        </Routes>
      </MemoryRouter>
    );

    // Component will use useParams() and get id="42"
    expect(screen.getByText(/Product 42/i)).toBeInTheDocument();
  });

  it('shows error for invalid product ID', () => {
    render(
      <MemoryRouter initialEntries={['/products/invalid']}>
        <Routes>
          <Route path="/products/:id" element={<ProductDetail />} />
        </Routes>
      </MemoryRouter>
    );

    expect(screen.getByText(/Invalid product ID/i)).toBeInTheDocument();
  });
});

# Performance Considerations

# Parameter Parsing Cost

For applications with many parameters, consider memoization:

typescript 
import { useParams, useMemo } from 'react-router-dom';

interface PostParams {
  year: string;
  month: string;
  day: string;
}

function PostArchive() {
  const { year, month, day } = useParams<PostParams>();

  // Memoize parsed values to avoid re-parsing on every render
  const parsedDate = useMemo(() => {
    if (!year || !month || !day) return null;
    
    try {
      return new Date(
        parseInt(year),
        parseInt(month) - 1,
        parseInt(day)
      );
    } catch {
      return null;
    }
  }, [year, month, day]);

  if (!parsedDate) return <div>Invalid date</div>;

  return <div>Posts from {parsedDate.toDateString()}</div>;
}

# Avoiding Unnecessary Re-renders

Use proper dependency arrays in effects:

typescript 
import { useParams, useEffect } from 'react';

function ProductPage() {
  const { id } = useParams<{ id: string }>();
  
  useEffect(() => {
    // ❌ Dependencies should include id, not the entire params object
    // const params = useParams();
    // useEffect(() => { ... }, [params]); // Causes infinite loops
    
    // ✅ Correct: Depend on specific values
    fetchProduct(id);
  }, [id]); // Only re-run when id changes
}

# Comparing with Alternative Approaches

# useParams vs Props

typescript 
// Option 1: Using useParams (recommended for routing)
function ProductPage() {
  const { id } = useParams();
  return <div>Product {id}</div>;
}

// Option 2: Using props (not recommended with React Router)
interface ProductProps {
  id: string;
}

function ProductPage({ id }: ProductProps) {
  return <div>Product {id}</div>;
}

// Issue: When using React Router, you can't pass props to route components
// { path: '/products/:id', element: <ProductPage /> }
// // No way to pass id as a prop here!

# useParams vs State

typescript 
// ❌ Wrong: Using state to store URL parameter
function ProductPage() {
  const [id, setId] = useState<string | null>(null);
  const { id: urlId } = useParams();

  useEffect(() => {
    setId(urlId);
  }, [urlId]);

  return <div>Product {id}</div>;
}

// ✅ Correct: Use URL parameter directly
function ProductPage() {
  const { id } = useParams();
  return <div>Product {id}</div>;
}

# useParams vs useLocation

typescript 
import { useParams, useLocation } from 'react-router-dom';

function Example() {
  const { id } = useParams();
  const location = useLocation();

  // useParams: Extracts specific route parameters
  // Returns: { id: "42" }

  // useLocation: Full URL information
  // Returns: {
  //   pathname: "/products/42",
  //   search: "?page=1",
  //   hash: "#reviews",
  //   ...
  // }

  // Use useParams for route values, useLocation for full URL
}

# FAQ

# Q: Why are useParams values always strings?

A: URL parameters are extracted from the URL path, which is always a string. Even if you have /products/123, the 123 is transmitted as the string "123". You must explicitly convert to numbers: parseInt(id, 10). This is a feature, not a bug—it forces you to validate input.

# Q: Can I have optional route parameters?

A: React Router doesn't support truly optional parameters in the path. Instead, use search parameters:

typescript 
// ❌ Don't try this
{ path: '/products/:id?', element: <ProductPage /> }

// ✅ Do this instead
{ path: '/products/:id', element: <ProductPage /> }
{ path: '/products', element: <ProductsPage /> }

// Or use search params
// /products?id=123
const searchParams = useSearchParams();
const id = searchParams.get('id');

# Q: How do I navigate with parameters?

A: Use navigate() or <Link> with template literals:

typescript 
import { useNavigate, Link } from 'react-router-dom';

function ProductList() {
  const navigate = useNavigate();

  return (
    <>
      {/* Using navigate */}
      <button onClick={() => navigate(`/products/42`)}>
        View Product 42
      </button>

      {/* Using Link */}
      <Link to={`/products/42`}>View Product 42</Link>
    </>
  );
}

# Q: What if a parameter doesn't match the route?

A: The route won't match, and your component won't render. For example:

typescript 
// Route: /products/:id
// URL: /products/abc/extra
// Result: No match, route not rendered

Make sure your navigation links match defined routes exactly.

# Q: Can I have parameters in the middle of a path?

A: Yes, and they're matched in order:

typescript 
// Route: /users/:userId/posts/:postId/comments/:commentId
// URL: /users/alice/posts/post-001/comments/comment-123
// Result: userId="alice", postId="post-001", commentId="comment-123"

# Q: Should I fetch data in useEffect or use a loader?

A: React Router v6.4+ provides loaders for data fetching before rendering:

typescript 
// Modern approach with loaders
const router = createBrowserRouter([
  {
    path: '/products/:id',
    element: <ProductPage />,
    loader: async ({ params }) => {
      return fetch(`/api/products/${params.id}`);
    },
  },
]);

// In component
import { useLoaderData } from 'react-router-dom';

function ProductPage() {
  const product = useLoaderData(); // Data already loaded!
  return <div>{product.name}</div>;
}

# Q: How do I prevent useParams from returning undefined?

A: Always validate parameters in your component. TypeScript helps but doesn't prevent runtime issues:

typescript 
import { useParams } from 'react-router-dom';
import { Navigate } from 'react-router-dom';

interface ProductParams {
  id: string;
}

function ProductPage() {
  const { id } = useParams<ProductParams>();

  // Validate required parameter
  if (!id) {
    return <Navigate to="/products" replace />;
  }

  // id is now safe to use
  const numId = parseInt(id, 10);
  if (isNaN(numId)) {
    return <Navigate to="/products" replace />;
  }

  return <div>Product {numId}</div>;
}

Questions? Share your routing patterns and useParams implementations in the comments. What routing challenges have you solved in your applications?

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