react-dom-lazyload-component

Lazyload your Components, Images or anything else. You can improve performance score lik Core Web Vitals.

Features

• ⚡️ Optimized performance: Reuses Intersection Observer instances where possible
• 💥 Minimum bundle: Around ~1kB
• 🛠 TypeScript: It'll fit right into your existing TypeScript project
• 💡 Easy to understand: You don't have to know about complex Intersection Observer API
• 😽 React 18: Optimized using Suspense and startTransition

Install

npm i react-dom-lazyload-component
yarn add react-dom-lazyload-component
pnpm add react-dom-lazyload-component

Usage

import { lazy } from 'react';
import LazyLoad, { useLazyLoad } from 'react-dom-lazyload-component';
import { Header, Main, Loading } from './MyComponents';

const Footer = React.lazy(() => import('./Footer'))

const App = () => (
    <>
        <Header />
        <Main />
        {/* Footer don't needed to be rendered first. */}
        {/* In this case, it will have been rendered in browser viewport. */}
        {/* This will optimize Core Web Vitals */}
        <LazyLoad
          as='footer'
          fallback={<Loading />}
          suspense
        >
          <Footer />
        </LazyLoad>
    </>
)

// You can also use hooks.
const App = () => {
    const { ref, isVisible } = useLazyLoad();

    return (
        <>
            <Header />
            <Main />
            <footer ref={ref}>{isVisible ? 'footer' : <Loading />}</footer>
        </>
    )
}

Props

useLazyLoad

Name	Required	Type	Default	Description
rootId	No	string	-	The id of element which is IntersectionObserver's target. If rootId is not specified, then the bounds of the actual document viewport are used. This prop wraps IntersectionObserver.root because of performance.
direction	No	'vertical' | 'horizontal'	'vertical'	Direction which user will scroll.
margin	No	string	'0px'	Margin around the root element. For examples, if direction is vertical and margin is 200px, IntersectionObserver.thresholds is 200px 0px.
forceVisible	No	boolean	false	You can forces the component to display regardless of whether the element is visible in the viewport.
once	No	boolean	true	You can control whether the element in the viewport is shown at once or not.

The return value is ref and isVisible. You can use ref to attach to the element you want to observe, and isVisible to determine if the element is visible in the viewport.

LazyLoad

You can specify the following props in addition to the useLazyLoad props.

Name	Required	Type	Default	Description
children	Yes	ReactNode	-	Component is rendered when it is in the viewport. Automatically enable React.Suspense if you use React.lazy .
fallback	No	ReactNode	-	Component is rendered when it is not in the viewport.
as	No	string	div	You can specify tag name to LazyLoad component.
suspense	No	boolean	false	You can use React.Suspense .
onVisible	No	() => void	-	Callback function called when the component has been visible.

LazyLoad also can be received props like className, style and id.

Browser Support

Please see Intersection Observer API.

Demo

https://hiroki0525.github.io/react-dom-lazyload-component/