setClass(i, a) {
    for (const n of i.split(",")) {
      const u = this.vertices.get(n);
      u && u.classes.push(a);
      const l = this.edges.find((c) => c.id === n);
      l && l.classes.push(a);
      const f = this.subGraphLookup.get(n);
      f && f.classes.push(a);
    }
  }
Called by parser when a special node is found, e.g. a clickable element.

@param ids - Comma separated list of ids
@param className - Class to add