Sugiyama algorithm: removing fake nodes

removeFakeNodes.js

var unlinkFakeNode = function (fakeNode) {
  // fake node: remove and connect nodes that it is connecting
  var previousNodes = fakeNode.previousNodes.slice(0); // copy since it's going to be modified
  previousNodes.forEach(function (previousNode) {
    // previous --> next1, previous --> next2, etc
    fakeNode.nextNodes.forEach(function (nextNode) {
      sugiyamaService.connectNodes(previousNode, nextNode);
    });

    // previous --X--> fake
    sugiyamaService.disconnectNodes(previousNode, fakeNode);
  });

  var nextNodes = fakeNode.nextNodes.slice(0); // copy since it's going to be modified
  nextNodes.forEach(function (nextNode) {
    sugiyamaService.disconnectNodes(fakeNode, nextNode);
  });
};

var removeFakeNodesColumn = function (column) {
  var rowIndex = column.length;
  while (rowIndex--) {
    var node = column[rowIndex];
    if (sugiyamaService.isFakeNode(node)) {
      unlinkFakeNode(node);
      column.splice(rowIndex, 1);
    }
  }
};

sugiyamaService.removeFakeNodes = function (grid) {
  for (var columnIndex = 0; columnIndex < grid.length; columnIndex++) {
    removeFakeNodesColumn(grid[columnIndex]);
  }
};