@mapbox/scroll-restorer
Preserve the scroll state of document.scrollingElement while navigating programmatically through history states — that is, client-side routing.
Installation
npm install @mapbox/scroll-restorer
Usage
- Invoke the
startmethod when you would like to begin storing the browser's scroll position in history states, likely when your application mounts. - Invoke the
stopmethod when you would like to stop the restoration of scroll position, likely when your application unmounts.
Have a look at an example using React Router.
API
start
scrollRestorer.start([options])
Starts tracking the user's scroll position.
options
autoRestore
Type: boolean.
Default: true.
When true, scroll-restorer will attempt to restore the scroll position on each popstate event. Set this to false if you want to manually control the scroll position restoration (e.g. you may wish to call restoreScroll at a very specific point in your application's rendering lifecycle).
captureScrollDebounce
Type: number.
Default: 50.
The number of milliseconds by which the scroll-capturing function should be debounced.
end
scrollRestorer.end()
End scroll-restorer's behavior.
getSavedScroll
scrollRestorer.getSavedScroll([input])
Returns the scroll position retrieved from window.history or an optional popstate event.
When the autoRestore option of start is true, this method will be invoked automatically, so you only want to use it manually if you've set autoRestore to false.
input
Type: { state: Object }, either window.history or a popstate event.
Default: window.history.
restoreScroll
scrollRestorer.restoreScroll([input, attempts])
Manually restore the scroll position for a given history state or popstate event.
When the autoRestore option of start is true, this method will be invoked automatically, so you only want to use it manually if you've set autoRestore to false.
input
Type: { state: Object }, either window.history or a popstate event.
Default: window.history.
attempts
Type: number.
Default: 5.
The number of times to attempt adjusting the scroll position. scroll-restorer might need to make multiple attempts if the saved scroll state refers to a position that is not yet available because content is still loading.
React & React Router Example
import React, {Component} from 'react';
import {HashRouter, Link, Route} from 'react-router-dom';
import scrollRestorer from '@mapbox/scroll-restorer';
class ScrollRestorerExample extends Component {
componentDidMount() {
// Initiate the scroll position restoration behavior.
scrollRestorer.start();
}
componentWillUnmount() {
// Cease the scroll position restoration behavior.
scrollRestorer.stop();
}
getContent(numParagraphs) {
const paragraphArr = new Array(numParagraphs).fill();
return (
<div>
<h1>Here are {numParagraphs} paragraph elements, enjoy!</h1>
{paragraphArr.map((_, index) => <p key={index}>Paragraph #{index}.</p>)}
</div>
);
}
render() {
return (
<HashRouter>
<div>
<nav style={{background: '#fff', position: 'fixed', top: 0, left: 0, width: '100%'}}>
<Link to="/">Home</Link>
<Link to="/page-a">Page A</Link>
<Link to="/page-b">Page B</Link>
<Link to="/page-c">Page C</Link>
</nav>
<main style={{marginTop: '40px'}}>
<Route exact path="/" render={() => <h1>This is the home page.</h1>} />
<Route exact path="/page-a" render={() => this.getContent(5)} />
<Route exact path="/page-b" render={() => this.getContent(20)} />
<Route exact path="/page-c" render={() => this.getContent(100)} />
</main>
</div>
</HashRouter>
);
}
}
export default ScrollRestorerExample;