Function traverseEnterLeave

code/composition/public/app.js:2743–2781

* Traverses the ID hierarchy and invokes the supplied `cb` on any IDs that * should would receive a `mouseEnter` or `mouseLeave` event. * * Does not invoke the callback on the nearest common ancestor because nothing * "entered" or "left" that element.

(from, to, fn, argFrom, argTo)

 * "entered" or "left" that element.
 */
function traverseEnterLeave(from, to, fn, argFrom, argTo) {
  var common = from && to ? getLowestCommonAncestor(from, to) : null;
  var pathFrom = [];
  while (true) {
    if (!from) {
      break;
    }
    if (from === common) {
      break;
    }
    var alternate = from.alternate;
    if (alternate !== null && alternate === common) {
      break;
    }
    pathFrom.push(from);
    from = getParent(from);
  }
  var pathTo = [];
  while (true) {
    if (!to) {
      break;
    }
    if (to === common) {
      break;
    }
    var _alternate = to.alternate;
    if (_alternate !== null && _alternate === common) {
      break;
    }
    pathTo.push(to);
    to = getParent(to);
  }
  for (var i = 0; i < pathFrom.length; i++) {
    fn(pathFrom[i], 'bubbled', argFrom);
  }
  for (var _i = pathTo.length; _i-- > 0;) {
    fn(pathTo[_i], 'captured', argTo);
  }
}

/**
 * Some event types have a notion of different registration names for different