Function analyzeScrollEdgeState

src/utils/scroll-edge-state.ts:33–66

(
  inputNodes: readonly (RawSnapshotNode | SnapshotNode)[] | undefined,
  edge: ScrollEdge,
  target: ScrollEdgeTarget = {},
)

const SCROLL_SIGNATURE_RECT_PRECISION = 1;

function analyzeScrollEdgeState(
  inputNodes: readonly (RawSnapshotNode | SnapshotNode)[] | undefined,
  edge: ScrollEdge,
  target: ScrollEdgeTarget = {},
): ScrollEdgeState {
  const nodes = ensureSnapshotNodes(inputNodes ?? []);
  if (nodes.length === 0) {
    return {
      canScroll: false,
      emptySnapshot: true,
      signature: '',
    };
  }

  const hiddenHints = deriveMobileSnapshotHiddenContentHints(nodes);
  const container = selectScrollContainer(nodes, hiddenHints, edge, target);
  const signatureNodes = container ? collectSubtreeNodes(nodes, container.index) : nodes;
  const signature = buildScrollStateSignature(signatureNodes);
  if (!container) {
    return {
      canScroll: false,
      emptySnapshot: false,
      signature,
    };
  }

  const canScroll = hasHiddenContentAtEdge(container, hiddenHints.get(container.index), edge);
  return {
    canScroll,
    emptySnapshot: false,
    signature,
    scope: buildScrollContainerScope(container),
  };
}

export async function captureScrollEdgeState(params: {
  edge: ScrollEdge;