Trigger组件中getPopupStyle方法内的switch语句可能会出现暂时性死区问题？？？

[lynn1286]

switch (props.position) {
    case 'top': {
      style.top = top - contentSize.height - alignTop;
      style.left = left + width / 2 - contentSize.width / 2;
      autoPosition('top') && (realPosition = 'bottom');
      style.left += horizontalOffset;

      const arrowLeft = left - Number(style.left) + width / 2;
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    }
    case 'tl':
      style.top = top - contentSize.height - alignTop;
      style.left = left;
      autoPosition('top') && (realPosition = 'bl');
      style.left += horizontalOffset;
      let arrowLeft = left - Number(style.left) + Math.min(width / 2, 50);
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    case 'tr':
      style.top = -content.clientHeight + top - alignTop;
      style.left = left + width - contentSize.width;
      autoPosition('top') && (realPosition = 'br');
      style.left += horizontalOffset;
      arrowLeft = left - Number(style.left) + Math.max(width / 2, width - 50);
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    case 'bottom': {
      style.top = height + top + alignBottom;
      style.left = left + width / 2 - contentSize.width / 2;
      autoPosition('bottom') && (realPosition = 'top');
      style.left += horizontalOffset;

      const arrowLeft = left - Number(style.left) + width / 2;
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    }
    case 'bl':
      style.top = height + top + alignBottom;
      style.left = left;
      autoPosition('bottom') && (realPosition = 'tl');
      style.left += horizontalOffset;
      arrowLeft = left - Number(style.left) + Math.min(width / 2, 50);
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    case 'br':
      style.top = height + top + alignBottom;
      style.left = left + width - contentSize.width;
      autoPosition('bottom') && (realPosition = 'tr');
      style.left += horizontalOffset;
      arrowLeft = left - Number(style.left) + Math.max(width / 2, width - 50);
      arrowStyle.left = getInsideValue(12, contentSize.width - 12, arrowLeft);
      break;
    case 'left': {
      style.top = top + height / 2 - contentSize.height / 2;
      style.left = left - contentSize.width - alignLeft;
      autoPosition('left') && (realPosition = 'right');
      style.top += verticalOffset;
      const arrowTop = top - Number(style.top) + height / 2;
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    }

    case 'lt':
      style.top = top;
      style.left = left - contentSize.width - alignLeft;
      autoPosition('left') && (realPosition = 'rt');
      style.top += verticalOffset;
      let arrowTop = top - Number(style.top) + Math.min(height / 2, 50);
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    case 'lb':
      style.top = top + height - contentSize.height;
      style.left = left - contentSize.width - alignLeft;
      autoPosition('left') && (realPosition = 'rb');
      style.top += verticalOffset;

      arrowTop = top - Number(style.top) + Math.max(height / 2, height - 50);
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    case 'right': {
      style.top = top + height / 2 - contentSize.height / 2;
      style.left = width + left + alignRight;
      autoPosition('right') && (realPosition = 'left');
      style.top += verticalOffset;

      const arrowTop = top - Number(style.top) + height / 2;
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    }
    case 'rt':
      style.top = top;
      style.left = width + left + alignRight;
      autoPosition('right') && (realPosition = 'lt');
      style.top += verticalOffset;

      arrowTop = top - Number(style.top) + Math.min(height / 2, 50);
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    case 'rb':
      style.top = top + height - contentSize.height;
      style.left = width + left + alignRight;
      autoPosition('right') && (realPosition = 'lb');
      style.top += verticalOffset;

      arrowTop = top - Number(style.top) + Math.max(height / 2, height - 50);
      arrowStyle.top = getInsideValue(12, contentSize.height - 12, arrowTop);
      break;
    default:
      break;
  }

如果switch语句直接匹配bl的场景下，arrowLeft 变量会出出现暂时性死区吗？
不应该把 let 声明在 switch外部吗？