@atlaskit/editor-plugin-show-diff/dist/es2019/pm-plugins/scrollToDiff.js

ShowDiff plugin for @atlaskit/editor-core

import { isDiffDecoration } from './decorations/decorationKeys';

/**
 * Extra space above the scrolled-to element so it does not sit flush under the
 * viewport edge (helps with sticky table headers, toolbars, etc.).
 *
 * Implemented with `scroll-margin-top` so we still use the browser’s native
 * `scrollIntoView`, which scrolls every relevant scrollport (nested containers
 * and the window). A single manual `scrollTop` on one ancestor often misses
 * outer scroll or mis-identifies the active scroll container.
 */
const SCROLL_TOP_MARGIN_PX = 100;

/**
 * Returns the resolved HTMLElement for a given DOM node, walking up to the
 * parent element if the node itself is not an Element (e.g. a text node).
 */
function scrollToSelection(node) {
  const element = node instanceof Element ? node : (node === null || node === void 0 ? void 0 : node.parentElement) instanceof Element ? node.parentElement : null;
  if (!(element instanceof HTMLElement)) {
    return;
  }

  // scroll-margin is included in scroll-into-view math; it does not change layout.
  const previousScrollMarginTop = element.style.scrollMarginTop;
  element.style.scrollMarginTop = `${SCROLL_TOP_MARGIN_PX}px`;
  try {
    element.scrollIntoView({
      behavior: 'smooth',
      block: 'start'
    });
  } finally {
    element.style.scrollMarginTop = previousScrollMarginTop;
  }
}

/**
 * Schedules scrolling to the decoration at the given index after the next frame. Defaults to the
 * first decoration when no index is provided.
 *
 * @returns A function that cancels the scheduled `requestAnimationFrame` if it has not run yet.
 */
export const scrollToDecoration = (view, decorations, activeIndex = 0) => {
  const decoration = decorations[activeIndex];
  if (!decoration) {
    return () => {};
  }
  let rafId = requestAnimationFrame(() => {
    rafId = null;
    if (isDiffDecoration(decoration) && decoration.spec.decorationType === 'widget') {
      var _decoration$type;
      // @ts-expect-error - decoration.type is not typed public API
      const widgetDom = decoration === null || decoration === void 0 ? void 0 : (_decoration$type = decoration.type) === null || _decoration$type === void 0 ? void 0 : _decoration$type.toDOM;
      scrollToSelection(widgetDom);
    } else {
      var _view$domAtPos;
      const targetNode = view.nodeDOM(decoration === null || decoration === void 0 ? void 0 : decoration.from);
      const node = targetNode instanceof Element ? targetNode : (_view$domAtPos = view.domAtPos(decoration === null || decoration === void 0 ? void 0 : decoration.from)) === null || _view$domAtPos === void 0 ? void 0 : _view$domAtPos.node;
      scrollToSelection(node);
    }
  });
  return () => {
    if (rafId !== null) {
      cancelAnimationFrame(rafId);
      rafId = null;
    }
  };
};