Route Groups in Next.js are an advanced routing feature introduced to help you organize routes without affecting the URL structure. This feature is especially useful in applications with complex directory structures or when using the App Router introduced in Next.js 13. By grouping routes, you can improve code organization, reuse layout components, and make the overall routing system more maintainable.

1. What are Route Groups?

Route Groups allow you to group related routes together while keeping them separate from the URL structure. This means you can create nested folders in your project to organize your code logically without the grouping folder being reflected in the final URL path.

This is particularly useful when:

• You want to share layouts or logic between multiple pages.
• You want a clean and simplified URL structure.
• You need a more organized way to manage related components.

2. Basic Usage of Route Groups

Route Groups are defined by wrapping the route folder name in parentheses (()). This signals to Next.js that the folder should act as a grouping but not impact the URL.

a. Example Structure with Route Groups

Suppose you have a blog and an admin panel that share certain layouts or components. You can use Route Groups to manage these routes effectively:

• Directory Structure:

  app/
    (blog)/
      layout.js
      posts/
        page.js
        [slug]/
          page.js
    (admin)/
      layout.js
      dashboard/
        page.js
      users/
        page.js
    page.js
  

• Explanation:

  • (blog) and (admin) are route group folders.
  • These folder names do not affect the final URL path.
  • This allows you to organize your project without changing the URLs that are exposed to users.

  For example:

  • A request to /posts will render posts/page.js.
  • The URL for viewing a blog post like /posts/hello-world would come from posts/[slug]/page.js.
  • The route group (blog) is used only for internal organization and has no effect on the URL path.

3. Layouts and Route Groups

Route Groups are particularly useful when you want to share a layout between different routes. With the App Router in Next.js 13, layouts are composable and can be reused across routes. Route Groups let you organize routes that share a common layout without affecting the URL.

a. Example with Shared Layouts

In the above structure, both the (blog) and (admin) groups have their own layout.js files. This means:

• (blog)/layout.js: This layout can be used for all routes under the blog route group.
• (admin)/layout.js: This layout can be applied to routes under the admin route group.

// app/(blog)/layout.js
export default function BlogLayout({ children }) {
  return (
    <div>
      <header>Blog Header</header>
      <main>{children}</main>
      <footer>Blog Footer</footer>
    </div>
  );
}

• The BlogLayout component will wrap all blog pages.
• A request to /posts will apply the BlogLayout, even though the URL does not reflect the (blog) grouping.

4. Conditional Layouts with Route Groups

One of the great advantages of Route Groups is the ability to manage conditional layouts. You can have different layouts based on which route group is being accessed.

For example, you might want the admin pages to have a different layout from the blog pages:

// app/(admin)/layout.js
export default function AdminLayout({ children }) {
  return (
    <div>
      <nav>Admin Navigation</nav>
      <main>{children}</main>
    </div>
  );
}

This AdminLayout will apply only to routes under the (admin) group, such as /dashboard and /users, without affecting the blog URLs or components.

5. Combining Route Groups with Dynamic Routes

Route Groups can also work seamlessly with dynamic routes. You can create dynamic segments within a route group, and these dynamic routes will still not reflect the route group in the final URL.

• Example Directory Structure:

  app/
    (products)/
      [category]/
        page.js
  

In this example:

• The route group (products) allows you to organize product categories logically.
• The final URL for accessing a specific category, like /electronics, is derived from [category]/page.js.
• The (products) folder does not appear in the final URL.

6. Benefits of Using Route Groups

• Clean URL Structure: Keep URLs user-friendly and free of unnecessary segments. Route groups allow you to organize your project internally without changing how users interact with URLs.
• Code Organization: Group related components logically in the file system, which makes maintaining larger projects easier.
• Reusable Layouts: Share layout components easily across grouped routes without duplicating code or changing the URL structure.
• Conditional Rendering: Use different layouts or components for different parts of your application (e.g., admin vs. public pages).

7. Advanced Example: Nested Route Groups

You can nest Route Groups if your application structure is more complex. For instance, an e-commerce site might have a public-facing store, an admin area, and customer dashboards, each with multiple levels of grouping.

• Directory Structure:

  app/
    (store)/
      products/
        page.js
        [id]/
          page.js
      cart/
        page.js
    (admin)/
      (settings)/
        users/
          page.js
        roles/
          page.js
    (customer)/
      dashboard/
        page.js
      orders/
        page.js
  

• Explanation:

  • (store): This route group can organize all the public-facing store-related routes.
  • (admin): This route group handles admin-related pages.
  • (settings): Nested within (admin), providing further organization for settings-related pages.
  • (customer): Handles pages specific to logged-in customers.

• URL Paths:

  • /products: Shows the products list, rendered from products/page.js.
  • /products/123: Shows a specific product, rendered from products/[id]/page.js.
  • /dashboard: Shows the customer dashboard, rendered from dashboard/page.js.

Despite the complex folder structure, the URLs are kept clean and do not reflect any of the route groups.

Summary

Route Groups in Next.js are a powerful feature for organizing routes without affecting the URL structure. They help in managing complex directory structures, reusing layouts across multiple routes, and keeping URLs clean and user-friendly. Key features of Route Groups include:

1. Grouping Routes Without Changing URLs: Use parentheses to define route groups without affecting the final URL path.
2. Shared Layouts: Use route groups to share layouts across logically related routes, improving consistency and reducing code duplication.
3. Conditional Layouts: Create specific layouts for different parts of the application using route groups.
4. Dynamic Routes: Combine route groups with dynamic segments for a more flexible, clean, and user-friendly URL system.
5. Complex Nesting: Route groups can be nested, providing even more control over code organization without impacting the URL structure.

By using Route Groups effectively, you can create well-structured, maintainable Next.js applications that offer a great user experience while keeping your codebase clean and organized.