Function selectScrollContainer

src/utils/scroll-edge-state.ts:168–209

(
  nodes: SnapshotNode[],
  hiddenHints: Map<number, HiddenContentHint>,
  edge: ScrollEdge,
  target: ScrollEdgeTarget,
)

}

function selectScrollContainer(
  nodes: SnapshotNode[],
  hiddenHints: Map<number, HiddenContentHint>,
  edge: ScrollEdge,
  target: ScrollEdgeTarget,
): SnapshotNode | null {
  const byIndex = new Map(nodes.map((node) => [node.index, node]));
  const scrollables = nodes.filter((node) => isScrollableNodeLike(node) && isUsableRect(node.rect));
  if (scrollables.length === 0) {
    return null;
  }

  const targetAncestor = findNearestScrollableAncestor(target.nodeIndex, byIndex);
  if (targetAncestor) {
    return targetAncestor;
  }

  const targetPoint = target.point;
  if (targetPoint) {
    const containing = scrollables
      .filter((node) => node.rect && containsPoint(node.rect, targetPoint))
      .sort(compareSpecificScrollContainer);
    if (containing.length > 0) {
      const withHiddenEdge = containing.find((node) =>
        hasHiddenContentAtEdge(node, hiddenHints.get(node.index), edge),
      );
      return withHiddenEdge ?? containing[0] ?? null;
    }
  }

  const withHiddenEdge = scrollables
    .filter((node) => hasHiddenContentAtEdge(node, hiddenHints.get(node.index), edge))
    .sort(compareBroadScrollContainer);
  if (withHiddenEdge.length > 0) {
    return withHiddenEdge[0] ?? null;
  }

  const visibleScrollables = scrollables
    .filter((node) => isNodeVisibleInEffectiveViewport(node, nodes))
    .sort(compareBroadScrollContainer);
  return visibleScrollables[0] ?? scrollables.sort(compareBroadScrollContainer)[0] ?? null;
}

function findNearestScrollableAncestor(
  nodeIndex: number | undefined,