function getReferenceOffsets(state, popper, reference) {
    var fixedPosition = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : null;

    var commonOffsetParent = fixedPosition ? getFixedPositionOffsetParent(popper) : findCommonOffsetParent(popper, reference);
    return getOffsetRectRelativeToArbitraryNode(reference, commonOffsetParent, fixedPosition);
  }
Get offsets to the reference element
@method
@memberof Popper.Utils
@param {Object} state
@param {Element} popper - the popper element
@param {Element} reference - the reference element (the popper will be relative to this)
@param {Element} fixedPosition - is in fixed position mode
@returns {Object} An object containing the offsets which will be applied to the popper