在mongodb中查询符合条件的文档及其所有子文档

function findDocuments(db, collectionName, query) {
  const collection = db.collection(collectionName);
  collection.find(query).forEach(document => {
    console.log(document);
    if (document.children) {
      findDocuments(db, collectionName, { _id: { $in: document.children } });
    }
  });
}

// 使用示例
const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017';
const dbName = 'yourDatabaseName';

MongoClient.connect(url, (err, client) => {
  if (err) {
    console.error('Failed to connect to MongoDB:', err);
    return;
  }

  const db = client.db(dbName);
  const collectionName = 'yourCollectionName';
  const query = { yourField: 'yourValue' };

  findDocuments(db, collectionName, query);

  client.close();
});

const pipeline = [
  { $match: { yourField: 'yourValue' } },
  {
    $graphLookup: {
      from: 'yourCollectionName',
      startWith: '$_id',
      connectFromField: '_id',
      connectToField: 'children',
      as: 'descendants'
    }
  }
];

// 使用示例
const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017';
const dbName = 'yourDatabaseName';

MongoClient.connect(url, (err, client) => {
  if (err) {
    console.error('Failed to connect to MongoDB:', err);
    return;
  }

  const db = client.db(dbName);
  const collectionName = 'yourCollectionName';

  db.collection(collectionName).aggregate(pipeline).toArray((err, result) => {
    if (err) {
      console.error('Failed to execute aggregation:', err);
      return;
    }

    console.log(result);

    client.close();
  });
});