How Next.js Rendering Functions

Next.js initially renders the requested page on the server and delivers it to the client. Afterward, React takes over for client-side rendering, a process known as React hydration. Instead of displaying a simple "Loading..." message, users are presented with a fully rendered HTML page that remains interactive.

In contrast, the typical flow for client-side rendering (i.e., standard React) consists of:

1. An HTML shell is served initially.
2. The browser fetches JavaScript files containing React.
3. The content is rendered and made interactive.

A common misconception is that you must choose between client-side or server-side rendering. The beauty of Next.js is its flexibility, allowing you to blend these rendering methods as necessary during the initial load.

Dynamic Import Mechanics

When constructing your view, you'll likely need to import certain elements from your project. While some components are fine to render on the server, others may need to load on the client for various reasons. Dynamic importing allows you to do just that, as components are downloaded in a separate batch file.

The benefits of using dynamic imports include:

• Reducing the initial page load size.
• Only importing modules when they are called in the code.
• Fetching content only when the component is rendered for the first time.
• Preventing additional fetch requests once the component is loaded.

Typically, React bundles everything via static imports, meaning all modules are delivered to the client at once. In contrast, dynamic imports allow for "lazy loading" of modules.

Utilizing Dynamic Loading Beyond Initial Load

Dynamic loading in Next.js isn't restricted to the first-page load; it can be applied elsewhere to optimize the initial bundle size. This technique allows you to load only what's necessary, enhancing responsiveness and creating a perception of faster loading times for users.

While you can use JavaScript's defer attribute, dynamic imports provide a superior solution.

Dynamic importing is a feature of JavaScript introduced in ES2020, and although Next.js has its unique implementation, the syntax differs slightly from standard JavaScript.

Here’s how the syntax looks:

// Statically imported module

import someStaticModule from 'some/module';

// Dynamically imported module

(async () => {

const { export1, export2 } = await import('path/to/some/module');

})();

Implementing Dynamic Import in Next.js for Client-Side Rendering

Now, let’s get to the practical part. The syntax for dynamic importing in Next.js is as follows:

const YourComponent = dynamic(() => import('./somefile'));

You will also need to import the dynamic function from Next.js:

import dynamic from "next/dynamic";

Then, you can use your component like any other:

<YourComponent />

Dynamic Imports with React.lazy

Alternatively, you can utilize React's lazy function for dynamic imports. The concept is similar, but the syntax is slightly different. Keep in mind that Next.js’s dynamic import is an extension of React's lazy, incorporating Suspense for delayed hydration until the Suspense boundary is resolved.

Here’s how the syntax looks with React.lazy:

const MyLazyComponent = lazy(() => import('path/to/component'));

Remember to import lazy from React:

import { lazy } from 'react';

Then, use the component as usual:

<MyLazyComponent />