Mastering Layouts in Next.js: A Comprehensive Guide
When building projects with Next.js, we often create an entire user interface by assembling isolated components. However, some parts of the interface require the same code snippets across multiple routes, such as the navigation header, footer, and sidebar. To manage this, we use layouts to structure the interface in a way that contains shared code snippets.
Understanding Layouts in Next.js
In this article, we’ll delve into managing layouts and nested layouts in Next.js using the Pages Router and the App Router. We’ll explore how to create a layout that shares header and footer content across multiple routes, implement nested layouts, and discuss the differences between the Pages Router and App Router approaches.
Creating a Layout with the Pages Router
To define a layout with the Pages routing system, we create a Layout component that renders any shared user interface and its children. We can then wrap each page’s rendered markup with the Layout component to achieve the desired UI.
Preserving State in a Shared Layout
However, simply wrapping each page’s render with the Layout component doesn’t preserve the state between page transitions. To overcome this, we can load the shared layout and other global files in the pages/_app.js file, which Next.js calls during each page initialization.
Creating Nested Layouts with the Pages Router
To create a nested shared layout, we need to nest a new layout that renders the sidebar navigation within the root layout. Next.js provides a way to compose layouts on a per-page basis using the getLayout function. This allows us to create multiple layouts and nest them or create a custom layout that applies to specific routes.
Managing Layouts in the App Router
Next.js 13 introduced the App Router file system, which enables first-class support for layouts, nested routes, and nested layouts. In the App routing system, we define a layout for any route segment within the app directory by exporting a default React component from a special file called layout.js.
Creating Nested Layouts in the App Router
Creating a nested shared layout in the App Router is incredibly easy and intuitive. We simply add a layout.js file inside the dashboard folder to define the UI, which will be nested within the root layout and wrap all the pages in the /dashboard/* route segment.
Implementing Parallel Routes
Parallel routes allow for simultaneous or conditional rendering of multiple pages within the same layout. We can create parallel routes by defining slots with the @folder convention and rendering multiple views within a layout.
Conclusion
Understanding how layouts work in Next.js is crucial for building complex projects with the framework. In this guide, we’ve covered all the necessary steps to structure the rendered UI with shared content and use it across multiple routes. We’ve discussed how to achieve layouts and nested layouts in both the Pages Router and the App Router, and learned how to implement parallel routes for the simultaneous rendering of multiple pages within a layout.