goog.dom.compareNodeOrder = function()

in asdoc/library/closure/goog/dom/dom.js [1543:1610]

• 48 lines of code
• 20 McCabe index (conditional complexity)

goog.dom.compareNodeOrder = function(node1, node2) {
  // Fall out quickly for equality.
  if (node1 == node2) {
    return 0;
  }

  // Use compareDocumentPosition where available
  if (node1.compareDocumentPosition) {
    // 4 is the bitmask for FOLLOWS.
    return node1.compareDocumentPosition(node2) & 2 ? 1 : -1;
  }

  // Special case for document nodes on IE 7 and 8.
  if (goog.userAgent.IE && !goog.userAgent.isDocumentModeOrHigher(9)) {
    if (node1.nodeType == goog.dom.NodeType.DOCUMENT) {
      return -1;
    }
    if (node2.nodeType == goog.dom.NodeType.DOCUMENT) {
      return 1;
    }
  }

  // Process in IE using sourceIndex - we check to see if the first node has
  // a source index or if its parent has one.
  if ('sourceIndex' in node1 ||
      (node1.parentNode && 'sourceIndex' in node1.parentNode)) {
    var isElement1 = node1.nodeType == goog.dom.NodeType.ELEMENT;
    var isElement2 = node2.nodeType == goog.dom.NodeType.ELEMENT;

    if (isElement1 && isElement2) {
      return node1.sourceIndex - node2.sourceIndex;
    } else {
      var parent1 = node1.parentNode;
      var parent2 = node2.parentNode;

      if (parent1 == parent2) {
        return goog.dom.compareSiblingOrder_(node1, node2);
      }

      if (!isElement1 && goog.dom.contains(parent1, node2)) {
        return -1 * goog.dom.compareParentsDescendantNodeIe_(node1, node2);
      }


      if (!isElement2 && goog.dom.contains(parent2, node1)) {
        return goog.dom.compareParentsDescendantNodeIe_(node2, node1);
      }

      return (isElement1 ? node1.sourceIndex : parent1.sourceIndex) -
          (isElement2 ? node2.sourceIndex : parent2.sourceIndex);
    }
  }

  // For Safari, we compare ranges.
  var doc = goog.dom.getOwnerDocument(node1);

  var range1, range2;
  range1 = doc.createRange();
  range1.selectNode(node1);
  range1.collapse(true);

  range2 = doc.createRange();
  range2.selectNode(node2);
  range2.collapse(true);

  return range1.compareBoundaryPoints(
      goog.global['Range'].START_TO_END, range2);
};