Code

function distributeLinks(node)
{
	var rect = node.getBounds();

	var bottomLinks = collectLinks(node,
		p => Math.abs(p.y - rect.bottom()) < 1);
	distributeX(node, bottomLinks);
}

function distributeX(node, links)
{
	var rect = node.getBounds();
	var nl = links.length;
	if (nl == 0)
		return;

	links.sort((l1, l2) =>
		otherEnd(l1, node).getCenter().x - otherEnd(l2, node).getCenter().x);
	var dx = rect.width / (nl + 1);
	var x = rect.left() + dx;
	for (var link of links)
	{
		if (link.getOrigin() == node)
		{
			var p = link.getStartPoint();
			p.x = x;
			link.setStartPoint(p);
		}
		else
		{
			var p = link.getEndPoint();
			p.x = x;
			link.setEndPoint(p);
		}
		x += dx;
		link.updateFromPoints();
	}
}

function collectLinks(node, predicate)
{
	var links = [];
	for (var link of node.getOutgoingLinks())
	{
		if (predicate(link.getStartPoint()))
			links.push(link);
	}
	for (var link of node.getIncomingLinks())
	{
		if (predicate(link.getEndPoint()))
			links.push(link);
	}
	return links;
}

function otherEnd(link, node)
{
	if (link.getOrigin() == node)
		return link.getDestination();
	else
		return link.getOrigin();
}