@quarterto/transitive-dependencies/transitive-dependencies.js

var Set = require('es6-set');
var arrayFrom = require('array-from');

module.exports = function transitiveDependencies(edges, start, out) {
  out = out || new Set();
  edges.forEach(function(edge) {
    if(edge[0] === start) {
      out.add(edge[1]);
      transitiveDependencies(edges, edge[1], out);
    }
  });
  return arrayFrom(out);
};