function processChildrenDetail()

in packages/designer/src/builtin-simulator/bem-tools/insertion.tsx [26:92]
59 lines of code
19 McCabe index (conditional complexity)

function processChildrenDetail(sim: ISimulatorHost, container: INode, detail: IPublicTypeLocationChildrenDetail): InsertionData {
  let edge = detail.edge || null;

  if (!edge) {
    edge = sim.computeRect(container);
    if (!edge) {
      return {};
    }
  }

  const ret: any = {
    edge,
    insertType: 'before',
  };

  if (detail.near) {
    const { node, pos, rect, align } = detail.near;
    ret.nearRect = rect || sim.computeRect(node);
    ret.nearNode = node;
    if (pos === 'replace') {
      // FIXME: ret.nearRect mybe null
      ret.coverRect = ret.nearRect;
      ret.insertType = 'cover';
    } else if (!ret.nearRect || (ret.nearRect.width === 0 && ret.nearRect.height === 0)) {
      ret.nearRect = ret.edge;
      ret.insertType = 'after';
      ret.vertical = isVertical(ret.nearRect);
    } else {
      ret.insertType = pos;
      ret.vertical = align ? align === 'V' : isVertical(ret.nearRect);
    }
    return ret;
  }

  // from outline-tree: has index, but no near
  // TODO: think of shadowNode & ConditionFlow
  const { index } = detail;
  if (index == null) {
    ret.coverRect = ret.edge;
    ret.insertType = 'cover';
    return ret;
  }
  let nearNode = container.children.get(index);
  if (!nearNode) {
    // index = 0, eg. nochild,
    nearNode = container.children.get(index > 0 ? index - 1 : 0);
    if (!nearNode) {
      ret.insertType = 'cover';
      ret.coverRect = edge;
      return ret;
    }
    ret.insertType = 'after';
  }
  if (nearNode) {
    ret.nearRect = sim.computeRect(nearNode);
    if (!ret.nearRect || (ret.nearRect.width === 0 && ret.nearRect.height === 0)) {
      ret.nearRect = ret.edge;
      ret.insertType = 'after';
    }
    ret.vertical = isVertical(ret.nearRect);
    ret.nearNode = nearNode;
  } else {
    ret.insertType = 'cover';
    ret.coverRect = edge;
  }
  return ret;
}