Load the React chunk CSS dynamically to optimize performance and only when it is necessary

Question

Load the React chunk CSS dynamically to optimize performance and only when it is necessary

After running an audit, Lighthouse is advising me to "Defer unused CSS" for my React app. Despite implementing code splitting and having separate CSS files for each chunk, the suggestion persists. One particular example highlighted by Lighthouse is the footer chunk. The footer component is lazy loaded using react-lazyload, meaning it will only load when scrolling down the page.

The issue arises as the CSS associated with the footer component is still being loaded into the head of the page even though the component itself is not rendered initially. This is what Lighthouse is flagging as problematic.

Is there a way to delay loading the CSS into the head until the specific component is actually rendered or needed?

Just to provide context, I am operating within a non-ejected Create React App (CRA) environment.

css reactjs optimization lazy-loading create-react-app

Answer 1

Answer №1

If you want to ensure everything loads smoothly, consider importing the stylesheet directly into the footer component using import './styles.css'

Alternatively, you could experiment with a different approach like this:

import * as React from 'react';

export default class MainPage extends React.Component{

    render(){
        return (
            <div>
                <link rel="stylesheet" type="text/css" href="./style.css" />
                <Footer/>
            </div>
        )
    }
};

Answer 2

If you want to ensure everything loads smoothly, consider importing the stylesheet directly into the footer component using import './styles.css'

Alternatively, you could experiment with a different approach like this:

import * as React from 'react';

export default class MainPage extends React.Component{

    render(){
        return (
            <div>
                <link rel="stylesheet" type="text/css" href="./style.css" />
                <Footer/>
            </div>
        )
    }
};

Answer 3

Answer №2

One approach that I have found to be effective is utilizing lazy-loading.

import { lazy, Suspense } from 'react';

Instead of directly importing your css files, consider placing them into a separate component:

import React from ‘react’;
import ‘/path/to/your/example.css’;
import ‘/path/to/your/other/example.css’;
const StylingComponent = ({ children }) => <>{children}</>;
export default StylingComponent;

Next, lazily load this component as follows:

const Styling = lazy(() => import('/path/to/your/StylingComponent'));

Lastly, utilize Suspense to ensure the css resources are loaded only when necessary:

<Suspense fallback={<></>}>
  <Styling />
</Suspense>

Answer 4

One approach that I have found to be effective is utilizing lazy-loading.

import { lazy, Suspense } from 'react';

Instead of directly importing your css files, consider placing them into a separate component:

import React from ‘react’;
import ‘/path/to/your/example.css’;
import ‘/path/to/your/other/example.css’;
const StylingComponent = ({ children }) => <>{children}</>;
export default StylingComponent;

Next, lazily load this component as follows:

const Styling = lazy(() => import('/path/to/your/StylingComponent'));

Lastly, utilize Suspense to ensure the css resources are loaded only when necessary:

<Suspense fallback={<></>}>
  <Styling />
</Suspense>

Load the React chunk CSS dynamically to optimize performance and only when it is necessary

Answer №1

Answer №2

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