Conditional CSS Next JS

What is Next JS?

Next.Js is a React framework that aids in building the foundation to develop web applications. By leveraging this framework, we can manage the necessary tools and configurations required for React development, as well as enhance the application with additional functionalities, features, and optimizations.

It is a publicly available comprehensive framework developed by Vercel, specifically crafted to streamline the development of dynamic web applications through the utilization of React.

It additionally provides server-side rendering and capabilities for generating static websites, aiding in the development of high-performing and search engine optimized web content.

What is Conditional CSS?

In Next.js, Conditional CSS pertains to the capability of loading CSS files or styles dynamically, depending on specific conditions. This feature proves beneficial for integrating functionalities such as dark mode implementation or loading CSS lazily for particular components on specific pages. Alternatively, it enables loading distinct stylesheets based on varying user roles within the environment.

Here are a few fundamental methods for incorporating conditional CSS loading in Next.js:

Dynamic Imports

We have the capability to employ dynamic imports in order to load CSS files conditionally depending on specific criteria. By leveraging dynamic imports, it becomes feasible to load distinct CSS files tailored for various themes like:

import dynamic from 'next/dynamic';
const MyComponent = ({ theme }) => {
  const DynamicCSS = dynamic(() =>
    import(`../styles/${theme}.css`).then((mod) => mod.default)
  );
return <DynamicCSS />;
};

In this instance, we are dealing with a theme that can function as either a prop or a state to dictate the loading of specific CSS files.

CSS-in-JS Libraries

If we opt for utilizing a CSS-in-JS library such as styled-component or emotion, we have the capability to selectively apply styles depending on the props or state.

import styled, { css } from 'styled-components';

const StyledComponent = styled.div`
  ${(props) =>
    props.condition &&
    css`
      background-color: red;
    `}
`;

In this scenario, the condition prop determines if the component will display a red background or not.

CSS Modules

By leveraging CSS modules, we have the capability to assign classes based on the props or state, mirroring the functionality of standard React Components.

For example:

import styles from './MyComponent.module.css';

const MyComponent = ({ theme }) => (
  <div className={theme === 'dark' ? styles.darkTheme : styles.lightTheme}>
    Content
  </div>
);

In this scenario, the CSS class assigned to the div container will be determined by the theme prop's value.

Here are a few instances demonstrating the implementation of conditional CSS within Next.js. The selection of a particular method will be dictated by the project's specific needs and individual preferences.

What are the benefits of Using Conditional CSS in Next JS?

In Next.js, conditional styling involves loading CSS based on specific conditions like the user's device, browser, or environmental variables. This functionality can be implemented through methods like CSS Modules, importing global CSS, or utilizing CSS-in-JS libraries in Next.js. There are advantages to leveraging conditional CSS in Next.js:

Optimized loading

We have the ability to enhance the efficiency of CSS loading by selectively incorporating the styles based on specific conditions. For instance, we could potentially load distinct styles for mobile and desktop users, thereby minimizing any superfluous load on the system.

Reduced code-splitting overhead

It automatically divides our JavaScript bundles to enhance performance. By selectively loading CSS, we can additionally minimize the size of these bundles, enhancing loading speed, particularly on slower networks or less capable devices.

Improved performance

By exclusively loading the essential styles for a particular page or component, we can decrease the quantity of CSS that the browser has to parse and implement. This results in quicker rendering times.

Enhanced user experience

Modifying styles according to the user's context can enhance the user experience by tailoring it to their preferences and optimizing the interface. For instance, adapting the design or font choices based on the user's device or screen dimensions can significantly improve usability.

Better browser compatibility

It also aids in providing browser-specific solutions or improvements, guaranteeing a uniform user experience across various browsers without unnecessarily increasing the size of your CSS file with polyfills or fallbacks.

Easier maintenance

When we maintain CSS in a modular and component-specific manner, it enhances code maintainability and minimizes the chances of unintended side effects when implementing modifications or introducing new functionalities.

Enhanced SEO

By optimizing website performance with conditional CSS loading, we can enhance SEO metrics like page load speed and mobile responsiveness, influencing search engine rankings, especially Google's algorithms.

Utilizing conditional CSS in Next.js enables customization of styles based on user contexts, improving performance and enhancing the user experience of our web application.

Limitations of using Next.js

Complexity for simple projects

For basic projects, the advanced capabilities of Next.js such as Server-Side Rendering (SSR) or Static Site Generation (SSG) may not be essential and could add unnecessary intricacy and extra processing load.

Learning curve

Similar to React.js, Next.js presents its own challenges for developers, particularly those who are unfamiliar with server-side rendering and build tools.

Limited flexibility

Next.js follows distinct conventions and relies on file system-based routing, which could potentially restrict adaptability for specific advanced scenarios or preexisting project setups.