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November 5, 2021 14:57
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scroll-restoration.tsx
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import * as React from 'react' | |
import {useLocation} from 'react-router-dom' | |
import {useTransition} from '@remix-run/react' | |
import {useBeforeUnload} from 'remix' | |
import {useSSRLayoutEffect} from './misc' | |
let firstRender = true | |
let positions: {[key: string]: number} = {} | |
const SESSION_STORAGE_KEY = 'kody_scroll_positions' | |
if (typeof window !== 'undefined') { | |
try { | |
positions = JSON.parse(sessionStorage.getItem(SESSION_STORAGE_KEY) ?? '{}') | |
} catch { | |
sessionStorage.removeItem(SESSION_STORAGE_KEY) | |
} | |
} | |
// shouldn't have to do it this way | |
// https://github.com/remix-run/remix/issues/240 | |
type LocationState = undefined | {isSubmission: boolean} | |
export function useScrollRestoration(enabled: boolean = true) { | |
const location = useLocation() | |
const latestLocationRef = React.useRef(location) | |
React.useEffect(() => { | |
latestLocationRef.current = location | |
}, [location]) | |
const isSubmission = (location.state as LocationState)?.isSubmission ?? false | |
const transition = useTransition() | |
const hash = | |
typeof window === 'undefined' ? location.hash : window.location.hash | |
React.useEffect(() => { | |
if (transition.location) { | |
positions[location.key] = window.scrollY | |
} | |
}, [transition, location]) | |
useBeforeUnload( | |
React.useCallback(() => { | |
positions[latestLocationRef.current.key] = window.scrollY | |
sessionStorage.setItem(SESSION_STORAGE_KEY, JSON.stringify(positions)) | |
}, []), | |
) | |
useSSRLayoutEffect(() => { | |
if (!enabled) return | |
if (transition.state !== 'idle') return | |
if (isSubmission) return | |
// don't restore scroll on initial render | |
if (firstRender) { | |
firstRender = false | |
return | |
} | |
if (hash) { | |
const el = document.getElementById(hash.slice(1)) | |
if (el) { | |
el.scrollIntoView({behavior: 'smooth'}) | |
return | |
} | |
} | |
const y = positions[location.key] | |
window.scrollTo(0, y ?? 0) | |
}, [transition.state, location.key, hash, positions, isSubmission]) | |
} | |
export function RestoreScrollPosition() { | |
return ( | |
<script | |
// restore scroll position ASAP: | |
// doing it inline like this means scroll position will happen before the page is hyrdated | |
// (or even if it's not). | |
dangerouslySetInnerHTML={{ | |
__html: ` | |
// yo, this code here ensures that you have a most excellent scroll management | |
// experience on the site. It's inline to make sure your scroll position is | |
// restored asap when refreshing or navigating back to the site using the back button | |
window.history.scrollRestoration = 'manual' | |
try { | |
const positions = JSON.parse(sessionStorage.getItem(${JSON.stringify( | |
SESSION_STORAGE_KEY, | |
)}) ?? '{}') | |
if (window.history.state.key) { | |
const storedY = positions[window.history.state.key] | |
if (typeof storedY === 'number') { | |
window.scrollTo(0, storedY) | |
} | |
} else { | |
// we want to make sure there's a key so the position can be associated | |
// with the key and restored if they leave and come back. | |
window.history.replaceState({key: Date.now()}, null) | |
} | |
} catch { | |
sessionStorage.removeItem('positions') | |
} | |
`, | |
}} | |
/> | |
) | |
} |
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