References

summary
public	F freeVertices(graph: any): Iterable Compute the free vertices of the input graph.
public	F * kahn1962(queue: any, graph: any): Iterable<any> Kahn's algorithm for topological sorting. See https://en.wikipedia.org/wiki/Topological_sorting#CITEREFKahn1962
public	F * sorted(edges: Iterable<any>, breakTies: Function): Iterable<any> Sort the vertices topologically breaking ties according to a given function.
public	F subroutine(queue: any, graph: any): Iterable<any> Sort the vertices topologically using a queue to order the free vertices.