hasGraphCycle.js

import mongoose from 'mongoose';
import UserModel from './UserModel';

export default async (parentId, leafId) => {
  const searchResult = await UserModel.aggregate([
    { $match: { _id: parentId.toString() } },
    {
      $graphLookup: {
        from: 'User',
        startWith: '$manager',
        connectFromField: 'manager',
        connectToField: '_id',
        as: 'connection',
      },
    },
  ]);

  if (!searchResult || !Array.isArray(searchResult) || searchResult.length < 1) {
    return false;
  }

  return !!searchResult[0].connection.find(doc => doc._id.equals(leafId.toString()));
};