feat: support horizontal scroll (#4)

Co-authored-by: Kent C. Dodds <[email protected]>
Co-authored-by: Kent C. Dodds <[email protected]>

Author: na2hiro

src/index.tsx

@@ -2,13 +2,22 @@ import * as React from 'react'
 import { useCallback, useEffect } from 'react'
 import { useBeforeUnload, useLocation, useNavigation } from 'react-router-dom'
 
+type Direction = "vertical" | "horizontal";
+type ScrollAttribute = "scrollTop" | "scrollLeft";
+const DIRECTION: { [direction in Direction]: ScrollAttribute } = {
+	vertical: 'scrollTop',
+	horizontal: 'scrollLeft',
+};
+
 export function ElementScrollRestoration({
 	elementQuery,
+	direction = "vertical",
 	...props
-}: { elementQuery: string } & React.HTMLProps<HTMLScriptElement>) {
+}: { elementQuery: string; direction?: Direction } & React.HTMLProps<HTMLScriptElement>) {
 	const STORAGE_KEY = `position:${elementQuery}`
 	const navigation = useNavigation()
 	const location = useLocation()
+	const scrollAttribute = DIRECTION[direction]
 
 	const updatePositions = useCallback(() => {
 		const element = document.querySelector(elementQuery)
@@ -26,7 +35,7 @@ export function ElementScrollRestoration({
 		}
 		const newPositions = {
 			...positions,
-			[location.key]: element.scrollTop,
+			[location.key]: element[scrollAttribute],
 		}
 		sessionStorage.setItem(STORAGE_KEY, JSON.stringify(newPositions))
 	}, [STORAGE_KEY, elementQuery, location.key])
@@ -39,9 +48,9 @@ export function ElementScrollRestoration({
 				const positions = JSON.parse(
 					sessionStorage.getItem(STORAGE_KEY) || '{}',
 				) as any
-				const storedY = positions[window.history.state.key]
-				if (typeof storedY === 'number') {
-					element.scrollTop = storedY
+				const stored = positions[window.history.state.key]
+				if (typeof stored === 'number') {
+					element[scrollAttribute] = stored
 				}
 			} catch (error: unknown) {
 				console.error(error)
@@ -56,7 +65,7 @@ export function ElementScrollRestoration({
 		updatePositions()
 	})
 
-	function restoreScroll(storageKey: string, elementQuery: string) {
+	function restoreScroll(storageKey: string, elementQuery: string, scrollAttribute: ScrollAttribute) {
 		const element = document.querySelector(elementQuery)
 		if (!element) {
 			console.warn(`Element not found: ${elementQuery}. Cannot restore scroll.`)
@@ -70,9 +79,9 @@ export function ElementScrollRestoration({
 			const positions = JSON.parse(
 				sessionStorage.getItem(storageKey) || '{}',
 			) as any
-			const storedY = positions[window.history.state.key]
-			if (typeof storedY === 'number') {
-				element.scrollTop = storedY
+			const stored = positions[window.history.state.key]
+			if (typeof stored === 'number') {
+				element[scrollAttribute] = stored
 			}
 		} catch (error: unknown) {
 			console.error(error)
@@ -86,7 +95,7 @@ export function ElementScrollRestoration({
 			dangerouslySetInnerHTML={{
 				__html: `(${restoreScroll})(${JSON.stringify(
 					STORAGE_KEY,
-				)}, ${JSON.stringify(elementQuery)})`,
+				)}, ${JSON.stringify(elementQuery)}, ${JSON.stringify(scrollAttribute)})`,
 			}}
 		/>
 	)