function getBoundaries()

in js/popper.js [627:679]
39 lines of code
19 McCabe index (conditional complexity)

function getBoundaries(popper, reference, padding, boundariesElement) {
  var fixedPosition = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : false;

  // NOTE: 1 DOM access here

  var boundaries = { top: 0, left: 0 };
  var offsetParent = fixedPosition ? getFixedPositionOffsetParent(popper) : findCommonOffsetParent(popper, getReferenceNode(reference));

  // Handle viewport case
  if (boundariesElement === 'viewport') {
    boundaries = getViewportOffsetRectRelativeToArtbitraryNode(offsetParent, fixedPosition);
  } else {
    // Handle other cases based on DOM element used as boundaries
    var boundariesNode = void 0;
    if (boundariesElement === 'scrollParent') {
      boundariesNode = getScrollParent(getParentNode(reference));
      if (boundariesNode.nodeName === 'BODY') {
        boundariesNode = popper.ownerDocument.documentElement;
      }
    } else if (boundariesElement === 'window') {
      boundariesNode = popper.ownerDocument.documentElement;
    } else {
      boundariesNode = boundariesElement;
    }

    var offsets = getOffsetRectRelativeToArbitraryNode(boundariesNode, offsetParent, fixedPosition);

    // In case of HTML, we need a different computation
    if (boundariesNode.nodeName === 'HTML' && !isFixed(offsetParent)) {
      var _getWindowSizes = getWindowSizes(popper.ownerDocument),
          height = _getWindowSizes.height,
          width = _getWindowSizes.width;

      boundaries.top += offsets.top - offsets.marginTop;
      boundaries.bottom = height + offsets.top;
      boundaries.left += offsets.left - offsets.marginLeft;
      boundaries.right = width + offsets.left;
    } else {
      // for all the other DOM elements, this one is good
      boundaries = offsets;
    }
  }

  // Add paddings
  padding = padding || 0;
  var isPaddingNumber = typeof padding === 'number';
  boundaries.left += isPaddingNumber ? padding : padding.left || 0;
  boundaries.top += isPaddingNumber ? padding : padding.top || 0;
  boundaries.right -= isPaddingNumber ? padding : padding.right || 0;
  boundaries.bottom -= isPaddingNumber ? padding : padding.bottom || 0;

  return boundaries;
}