Bindings to a JS library with method overloads

I’m wrapping a JS/TS library, and everything works fine until I need to wrap a method that has an optional second argument. It starts like this:

module Graphology = {
  type directedGraph = {
    addNode: (string) => string,
    addEdge: (string, string) => string,
  }

  @new @module("graphology")
  external createDirectedGraph: unit => directedGraph = "DirectedGraph"
}

and this works. However, addNode() has an overload with an extra argument like here. What would be the way to wrap that?