Save and restore the scroll position

A horizontal rail forgets its offset every time it unmounts: route away and back, collapse a section, and it snaps to the start. This example saves the offset as the user scrolls and writes it back on mount, so the menu reappears exactly where they left it.
#01
#02
#03
#04
#05
#06
#07
#08
#09
#10
#11
#12
#13
#14

Scroll the row somewhere, unmount the menu, then mount it again — the rail comes back at the same offset.

How it works

Two callbacks carry the whole feature. onUpdate fires as the menu’s visibility state changes while the user scrolls; savePos reads api.scrollContainer.current.scrollLeft and writes it to sessionStorage. On the next mount, onInit assigns the saved value straight back to scrollLeft — a plain property write, so the restore is instant rather than an animation replaying in front of the user.

Surviving remounts, reloads and back navigation

sessionStorage outlives the component: client-side route changes, conditional renders and full page reloads all come back to the saved offset, and the value is per-tab, so two tabs don’t overwrite each other. For history navigation the story also sets window.history.scrollRestoration = ’manual’, keeping the browser’s own scroll restoration from fighting the manual one on back and forward.

Notes

Full source

Complete and copy-paste ready — this is the exact file behind the live-editable Storybook version.

Position.source.tsx
import 'react-horizontal-scrolling-menu/dist/styles.css';

import styled from '@emotion/styled';
import React from 'react';
import {
  type publicApiType,
  ScrollMenu,
  VisibilityContext,
} from 'react-horizontal-scrolling-menu';

export function Position() {
  const [items] = React.useState(() => getItems());
  const [selected, setSelected] = React.useState<string[]>([]);

  const isItemSelected = (id: string): boolean =>
    !!selected.find((el) => el === id);

  const handleItemClick = (itemId: string) => {
    const itemSelected = isItemSelected(itemId);

    setSelected((currentSelected: string[]) =>
      itemSelected
        ? currentSelected.filter((el) => el !== itemId)
        : currentSelected.concat(itemId),
    );
  };

  const { getPosition, setPosition, reset } = usePosition();
  const savePos = React.useCallback(
    (api: publicApiType) => {
      setPosition(api.scrollContainer.current?.scrollLeft ?? 0);
    },
    [setPosition],
  );
  const restorePosition = React.useCallback(
    (api: publicApiType) => {
      const node = api.scrollContainer.current;

      if (node) {
        node.scrollLeft = getPosition();
      }
    },
    [getPosition],
  );

  const [key, setKey] = React.useState(() => String(Math.random()));
  const reload = React.useCallback(() => setKey(String(Math.random())), []);

  return (
    <>
      <ScrollMenu
        LeftArrow={LeftArrow}
        RightArrow={RightArrow}
        onWheel={onWheel}
        onUpdate={savePos}
        onInit={restorePosition}
        key={key}
      >
        {items.map(({ id }) => (
          <Card
            title={id}
            itemId={id} // NOTE: itemId is required for track items
            key={id}
            onClick={() => handleItemClick(id)}
            selected={isItemSelected(id)}
          />
        ))}
      </ScrollMenu>
      <div>
        <button onClick={reset} data-testid="reset">
          Reset position
        </button>
        <button onClick={reload} data-testid="reload">
          Reload
        </button>
      </div>
    </>
  );
}

const usePosition = () => {
  React.useEffect(() => {
    window.history.scrollRestoration = 'manual';
  }, []);

  const setPosition = React.useCallback((pos: number | string) => {
    sessionStorage.setItem('position', String(pos));
  }, []);
  const getPosition = () => +(sessionStorage.getItem('position') || 0);
  const reset = React.useCallback(
    () => sessionStorage.removeItem('position'),
    [],
  );

  return { getPosition, setPosition, reset };
};

export default Position;

function LeftArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);

  const disabled = visibility.useLeftArrowVisible();

  return (
    <Arrow
      disabled={disabled}
      onClick={() => visibility.scrollPrev()}
      testId="left-arrow"
    >
      Left
    </Arrow>
  );
}

function RightArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);

  const disabled = visibility.useRightArrowVisible();

  return (
    <Arrow
      disabled={disabled}
      onClick={() => visibility.scrollNext()}
      testId="right-arrow"
    >
      Right
    </Arrow>
  );
}

function Arrow({
  children,
  disabled,
  onClick,
  className,
  testId,
}: {
  children: React.ReactNode;
  disabled: boolean;
  onClick: VoidFunction;
  className?: string;
  testId: string;
}) {
  return (
    <ArrowButton
      disabled={disabled}
      onClick={onClick}
      className={'arrow' + `-${className}`}
      data-testid={testId}
    >
      {children}
    </ArrowButton>
  );
}
const ArrowButton = styled('button')((props) => ({
  cursor: 'pointer',
  display: 'flex',
  flexDirection: 'column',
  justifyContent: 'center',
  marginBottom: '2px',
  opacity: props.disabled ? '0' : '1',
  userSelect: 'none',
  borderRadius: '6px',
  borderWidth: '1px',
}));

function Card({
  onClick,
  selected,
  title,
  itemId,
}: {
  onClick: (context: publicApiType) => void;
  selected: boolean;
  title: string;
  itemId: string;
}) {
  const visibility = React.useContext<publicApiType>(VisibilityContext);
  const isVisible = visibility.useIsVisible(itemId, true);

  return (
    <CardBody
      data-cy={itemId}
      onClick={() => onClick(visibility)}
      onKeyDown={(ev: React.KeyboardEvent) => {
        ev.code === 'Enter' && onClick(visibility);
      }}
      data-testid="card"
      role="button"
      tabIndex={0}
      className="card"
      visible={isVisible}
      selected={selected}
    >
      <div className="header">
        <div>{title}</div>
        <div className="visible">visible: {JSON.stringify(isVisible)}</div>
        <div className="selected">selected: {JSON.stringify(!!selected)}</div>
      </div>
      <div className="background" />
    </CardBody>
  );
}
const CardBody = styled('div')<{ selected?: boolean; visible?: boolean }>(
  (props) => ({
    border: '1px solid',
    display: 'inline-block',
    margin: '0 10px',
    width: '160px',
    userSelect: 'none',
    borderRadius: '8px',
    overflow: 'hidden',

    '& .header': {
      backgroundColor: 'white',
    },

    '& .visible': {
      backgroundColor: props.visible ? 'transparent' : 'gray',
    },

    '& .background': {
      backgroundColor: props.selected ? 'green' : 'bisque',
      height: '200px',
    },
  }),
);

const getId = (index: number) => `${'test'}${index}`;

const getItems = () =>
  Array(10)
    .fill(0)
    .map((_, ind) => ({ id: getId(ind) }));

function onWheel(apiObj: publicApiType, ev: React.WheelEvent): void {
  // NOTE: no good standart way to distinguish touchpad scrolling gestures
  // but can assume that gesture will affect X axis, mouse scroll only Y axis
  // of if deltaY too small probably is it touchpad
  const isThouchpad = Math.abs(ev.deltaX) !== 0 || Math.abs(ev.deltaY) < 15;

  if (isThouchpad) {
    ev.stopPropagation();
    return;
  }

  if (ev.deltaY < 0) {
    apiObj.scrollNext();
  } else {
    apiObj.scrollPrev();
  }
}

Related examples

All 21 examples