As the wiki demostrates, it seems to be suggested to set a label string for the graph instance by setGraph() . Actually, setGraph() and graph() are just a accessor to an internal private variable this._label, which can be any valid javascript expression. That's what the dagre uses to place the graph configurations like rankdir etc.
That's my confusion on setGraph(label) . Perhaps it could be better to describe it as some description for the graph, which could accept any valid javascript expression, maybe object the best.
BTW, thanks for making graphlib. It did a great job.