code: function _getOuterSize(gridSize, sizeScreen) {
    if ('lg' === sizeScreen) {
      if (gridSize && gridSize.lg) {
        return gridSize.lg;
      }
      else if (gridSize && gridSize.md) {
        return gridSize.md;
      }
      else if (gridSize && gridSize.sm) {
        return gridSize.sm;
      }
      else if (gridSize && gridSize.xs) {
        return gridSize.xs;
      }
    }
    else if ('md' === sizeScreen) {
      if (gridSize && gridSize.md) {
        return gridSize.md;
      }
      else if (gridSize && gridSize.sm) {
        return gridSize.sm;
      }
      else if (gridSize && gridSize.xs) {
        return gridSize.xs;
      }
    }
    else if ('sm' === sizeScreen) {
      if (gridSize && gridSize.sm) {
        return gridSize.sm;
      }
      else if (gridSize && gridSize.xs) {
        return gridSize.xs;
      }
    }
    else if ('xs' === sizeScreen) {
      if (gridSize && gridSize.xs) {
        return gridSize.xs;
      }
    }
    // default
    return grid;
  }
docs: determine size of outer element