react-laz-y-component-loader

Lazy load your components when they appear in the viewport.

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Lazy load your components when they appear in the viewport.

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About The Project

By combining the power of browser Intersection Observer API and React Lazy API I've created a simple component that will allow you to lazy load your component when it appears in the browser's viewport.

Don't load components that user won't see on the first render, React Laz-y will detect the scroll position for you and inject the correct code when it's actually needed.

Getting Started

To install, follow these few steps.

Prerequisites

Before you start, make sure you use:

  • React >= 16.6.0
  • npm
npm install npm@latest -g

Installation

  • Install with npm
    npm i react-laz-y-component-loader
    
    or
  • Install with yarn
    yarn add react-laz-y-component-loader
    

Usage

Basic example

Pass a component imported with React.lazy API as a children.

import React from 'react';
import ReactLazy from 'react-laz-y-component-loader';

const MyComponent = React.lazy(() => import('./MyComponent'));

function App() {
  return (
    <>
      <header style={{ height: '300vh' }}>
        <h1>My awesome title</h1>
      </header>
      <main>
        <ReactLazy>
          <MyComponent />
        </ReactLazy>
      </main>
    </>
  );
};

export default App;

Usage with rootMargin property

Pass the rootMargin props to increase or decrease the area of the root bounding box.

rootMargin props

import React from 'react';
import ReactLazy from 'react-laz-y-component-loader';

const MyComponent = React.lazy(() => import('./MyComponent'));

function App() {
  return (
    <>
      <header style={{ height: '300vh' }}>
        <h1>My awesome title</h1>
      </header>
      <main>
        <ReactLazy rootMargin="100px 0px">
          <MyComponent />
        </ReactLazy>
      </main>
    </>
  );
};

export default App;

Props

Name Type Default Required Description
children ReactElement undefined true Child element loaded with React.lazy API.
onLoad function () => {} false Function that will be fired when child element is loaded.
root HTMLElement viewport false Parent of the element that will be loaded.
rootMargin string "0px" false Defines margin of root bounding box. See more here.
threshold number || number[] 0 false Determines how much of the elements wrapper needs to intersect with the bounding box. See more here.
fallback ReactElement <div>Loading...</div> false Fallback element that will be rendered while target elements is being loaded.
wrapperClass string "" false Custom class for element's wrapper.
styles object {} false Custom styles for element's wrapper.

License

Distributed under the MIT License. See LICENSE for more information.

Contact

Maciek Grzybek - @maciek_g88 - maciekgrzybek1@gmail.com

Notes

  • Currently React Laz-y doesn't work with SSR due you React Lazy API limitations.
  • React Lazy API only supports default exports. There's a simple workaround that you can find here.
  • Intersection Observer API doesn't work with Internet Explorer. If you really need to support it, you can use polyfill. Simply import it in your project.

If you find any bugs or have a feature request, please open an issue on github!

The npm package download data comes from npm's download counts api and package details come from npms.io.