code: function getBordersSize(styles, axis) {
    const sideA = axis === 'x' ? 'Left' : 'Top';
    const sideB = sideA === 'Left' ? 'Right' : 'Bottom';
  
    return parseFloat(styles[`border${sideA}Width`], 10) + parseFloat(styles[`border${sideB}Width`], 10);
  }
docs: /*
  Helper to detect borders of a given element
  @method
  @memberof Popper.Utils
  @param {CSSStyleDeclaration} styles
  Result of `getStyleComputedProperty` on the given element
  @param {String} axis - `x` or `y`
  @return {number} borders - The borders size of the given axis