@atlaskit/drawer/dist/es2019/drawer-panel/hooks/use-prevent-programmatic-scroll.js

A drawer is a panel that slides in from the left side of the screen.

import { useCallback, useEffect, useLayoutEffect, useState } from 'react';
import { bind } from 'bind-event-listener';
import { fg } from '@atlaskit/platform-feature-flags/fg';

/**
 * Returns how far the body is scrolled from the top of the viewport.
 *
 * ⚠️ This is copied from `packages/design-system/modal-dialog/src/internal/hooks/use-prevent-programmatic-scroll.tsx`
 *
 *   ____
 * ||____|| <-- overflow
 *  |    |  <-- viewport
 *  |____|
 *
 * Scroll distance is the height of overflow outside the viewport.
 */
function getScrollDistance() {
  var _document$documentEle, _document$body;
  return window.pageYOffset || ((_document$documentEle = document.documentElement) === null || _document$documentEle === void 0 ? void 0 : _document$documentEle.scrollTop) || ((_document$body = document.body) === null || _document$body === void 0 ? void 0 : _document$body.scrollTop) || 0;
}

/**
 * Prevents programmatic scrolling of the viewport with `scrollIntoView`.
 * Should be used in conjunction with a scroll lock to prevent a user from scrolling.
 *
 * ⚠️ This is copied from `packages/design-system/modal-dialog/src/internal/hooks/use-prevent-programmatic-scroll.tsx`
 *
 * @returns scroll top offset of the viewport
 */
export default function usePreventProgrammaticScroll() {
  const [scrollTopOffset, setScrollTopOffset] = useState(0);
  useLayoutEffect(() => {
    setScrollTopOffset(getScrollDistance());
  }, []);
  const onWindowScroll = useCallback(() => {
    if (getScrollDistance() !== scrollTopOffset) {
      window.scrollTo(window.pageXOffset, scrollTopOffset);
    }
  }, [scrollTopOffset]);
  useEffect(() => {
    // The top-layer drawer relies on native modality + `DialogScrollLock`; the
    // programmatic-scroll guard is intentionally dropped under the flag.
    if (fg('platform-dst-top-layer')) {
      return;
    }
    return bind(window, {
      type: 'scroll',
      listener: onWindowScroll
    });
  }, [onWindowScroll]);
  return scrollTopOffset;
}