is a lightweight but powerful image component, which helps you handle image UX (user experience) and performance as a professional guy 🤓. It empowers the standard tag by many cool features without breaking your original development experience. Ideally, it can be an tag replacement for your React.js project. react-cool-img React.js img img Demo Example Features 🖼 Placeholders for satisfying various image loading states (e.g. loading image > actual image > error image). 🛋 Smart lazy loading with performant and efficient way, using . Intersection Observer 🤖 Built-in auto-retry mechanism. User won't miss out your important information. 🚫 Aborts any current image downloads on component unmount potentially saving bandwidth and browser resources. 🔍 Supports server-side rendering / Javascript is disabled / SEO. 📜 Supports type definition. TypeScript 🦔 Tiny size (~ 2KB gzipped). No external dependencies, aside for the and . react react-dom 🔧 Easy to use. Usage Example The of the component has been fine-tuned for the purpose of loading optimization. Let's start it as the following example. default props Img ; loadingImage ; errorImage ; App = ( import from 'react-cool-img' // Suggest to use low quality or vector images import from './images/loading.gif' import from './images/error.svg' const => () ); < = = = = /> Img placeholder {loadingImage} src "https://the-image-url" error {errorImage} alt "React Cool Img" Don't want an image placeholder? No worries, you can use or CSS for it. The component is fully compatible with the development experience of normal tag. inline styles img Img ; App = ( import from 'react-cool-img' const => () ); < = ' ', ' ', ' ' }} = = /> Img style {{ backgroundColor: grey width: 480 height: 320 src "https://the-image-url" alt "React Cool Img" The Smart Way to Load Images Lazy image loading via the is good. But could it be greater to download an image only when user want to see it? Or bypass lazy loading for ? The answer is yes and these features already be built into react-cool-img by the and props. Intersection Observer API cached images debounce cache By the prop, an image can wait to be downloaded while it's in the viewport for a set time. In cases where you have a long list of images that the user might scroll through inadvertently. At this time loading images can cause unnecessary waste of bandwidth and processing time. debounce Img ; defaultImg ; App = ( import from 'react-cool-img' import from './images/default.svg' const => () ); < = = = // ( ) = /> Img placeholder {defaultImg} src "https://the-image-url" debounce {1000} Default is 300 ms alt "React Cool Img" By the prop, images you already have cached will abort lazy loading until user visit your app next time. Lazy loading is set up for any remaining images which were not cached. This is helpful for UX, because there's not much extra work to load cached images immediately and is an easy win for making the UI looks more intuitive. cache Img ; defaultImg ; App = ( import from 'react-cool-img' import from './images/default.svg' const => () ); < = = // , = /> Img placeholder {defaultImg} src "https://the-image-url" cache Default is true just for demo alt "React Cool Img" JavaScript Availability and SEO There're two challenges when doing lazy image loading with server-side rendering. One is Javascript availability the other is SEO. Fortunately, we can use tag to solve these problems. It will render the actual image as fallback if Javascript is disabled thus user won't see the image which be stuck with the placeholder. Moreover, the tag ensure the image is indexed by search engine bots even if they cannot fully understand our JavaScript code. Take a look at how magic happens. <noscript> <noscript> Img = { ( <img class="image" src="https://the-placeholder-image" alt="There's no magic" /> <noscript> <img class="image" src="https://the-actual-image" alt="The magic begins in here..." /> </noscript> </> ); }; const => () // ... return <> Thanks for reading, for more usage details checkout the project's GitHub page: . https://github.com/wellyshen/react-cool-img You can also install this package is distributed via . npm $ yarn add react-cool-img $ npm install --save react-cool-img # or
