做一个适当的MongoDB查询（TypeError：将循环结构转换为JSON）
我正在查询我已经做了多次的事情。 看看，我似乎无法理解。
/* GET all things */ app.get('/things', function(req, res) { var search = req.query.search; console.log(search); //works properly and prints strings Thing.find({ name: {$regex : search}}, function(err, val) { if(err) throw error; console.log(val); // returns some horrible JSON res.send(JSON.stringify(val)); // Throws TypeError }); }) 我想也许我的查询是错误的，也许也许这是Mongo shell抛出的问题，但是当我走进Mongo shell。
use dbname
> db.booking.find({name: {$regex: "G"}})
>{ "_id" : ObjectId("58238283565e2c1940b16d48"), "name" : "Go to Lesters"}
这是我打印val时发生的情况。
Readable { pool: null, server: null, disconnectHandler: { s: { storedOps: [], storeOptions: [Object], topology: [Object] }, length: [Getter] }, bson: {}, ns: 'vectio.booking', cmd: { find: 'vectio.booking', limit: 0, skip: 0, query: { name: [Object] }, slaveOk: true, readPreference: { preference: 'primary', tags: undefined, options: [Object] } }, options: { skip: 0, limit: 0, raw: undefined, hint: null, timeout: undefined, slaveOk: true, readPreference: { preference: 'primary', tags: undefined, options: [Object] }, db: EventEmitter { domain: null, _events: {}, _eventsCount: 0, _maxListeners: undefined, s: [Object], serverConfig: [Getter], bufferMaxEntries: [Getter], databaseName: [Getter] }, promiseLibrary: [Function: Promise], disconnectHandler: { s: [Object], length: [Getter] } }, topology: EventEmitter { domain: null, _events: { reconnect: [Function], reconnectFailed: [Function], timeout: [Object], error: [Object], close: [Function], destroy: [Object], serverDescriptionChanged: [Function], serverHeartbeatStarted: [Function], serverHeartbeatSucceeded: [Function], serverHeartbeatFailed: [Function], serverOpening: [Function], serverClosed: [Function], topologyOpening: [Function], topologyClosed: [Function], topologyDescriptionChanged: [Function], attemptReconnect: [Function], monitoring: [Function] }, _eventsCount: 17, _maxListeners: undefined, id: 0, s: { options: [Object], logger: [Object], Cursor: [Object], bson: {}, pool: [Object], disconnectHandler: [Object], monitoring: true, inTopology: false, monitoringInterval: 5000, topologyId: -1 }, ismaster: { ismaster: true, maxBsonObjectSize: 16777216, maxMessageSizeBytes: 48000000, maxWriteBatchSize: 1000, localTime: 2016-11-09T20:41:56.152Z, maxWireVersion: 2, minWireVersion: 0, ok: 1 }, lastIsMasterMS: 6, monitoringProcessId: Timeout { _called: false, _idleTimeout: 5000, _idlePrev: [Object], _idleNext: [Object], _idleStart: 255, _onTimeout: [Function], _repeat: null }, initalConnect: false, wireProtocolHandler: {}, _type: 'server', clientInfo: { driver: [Object], os: [Object], platform: 'Node.js v6.2.1, LE, mongodb-core: 2.0.13' }, lastUpdateTime: 0, lastWriteDate: 0, staleness: 0 }, cursorState: { cursorId: null, cmd: { find: 'vectio.booking', limit: 0, skip: 0, query: [Object], slaveOk: true, readPreference: [Object] }, documents: [], cursorIndex: 0, dead: false, killed: false, init: false, notified: false, limit: 0, skip: 0, batchSize: 1000, currentLimit: 0, transforms: undefined }, logger: { className: 'Cursor' }, _readableState: ReadableState { objectMode: true, highWaterMark: 16, buffer: [], length: 0, pipes: null, pipesCount: 0, flowing: null, ended: false, endEmitted: false, reading: false, sync: true, needReadable: false, emittedReadable: false, readableListening: false, resumeScheduled: false, defaultEncoding: 'utf8', ranOut: false, awaitDrain: 0, readingMore: false, decoder: null, encoding: null }, readable: true, domain: null, _events: {}, _eventsCount: 0, _maxListeners: undefined, s: { numberOfRetries: 5, tailableRetryInterval: 500, currentNumberOfRetries: 5, state: 0, streamOptions: {}, bson: {}, ns: 'vectio.booking', cmd: { find: 'vectio.booking', limit: 0, skip: 0, query: [Object], slaveOk: true, readPreference: [Object] }, options: { skip: 0, limit: 0, raw: undefined, hint: null, timeout: undefined, slaveOk: true, readPreference: [Object], db: [Object], promiseLibrary: [Function: Promise], disconnectHandler: [Object] }, topology: EventEmitter { domain: null, _events: [Object], _eventsCount: 17, _maxListeners: undefined, id: 0, s: [Object], ismaster: [Object], lastIsMasterMS: 6, monitoringProcessId: [Object], initalConnect: false, wireProtocolHandler: {}, _type: 'server', clientInfo: [Object], lastUpdateTime: 0, lastWriteDate: 0, staleness: 0 }, topologyOptions: { host: 'localhost', port: 27017, disconnectHandler: [Object], cursorFactory: [Object], reconnect: true, emitError: true, size: 5, socketOptions: {}, clientInfo: [Object], readPreference: [Object], promiseLibrary: [Function: Promise], bson: {} }, promiseLibrary: [Function: Promise], currentDoc: null }, sortValue: undefined } /home/dilraj/Documents/Vectio/scenario-dilraj/node_modules/mongodb/lib/utils.js:99 process.nextTick(function() { throw err; }); ^ TypeError: Converting circular structure to JSON
我试图得到类似{ _id: ObjectId("58238283565e2c1940b16d48"), name: "Go to Lesters" }
或类似的东西，只要它是有道理的！ 我只是没有看到这样的事情。
我正在使用Node的Express JS框架，我唯一的模块是Nodemon，Express，bodyParser和Mongo。 没有其他的！ 谢谢，感谢爱！
您logging的对象是Mongo游标。 这有时候会很有用，但只是获取不是您所需要的文档。
Thing.find(query).toArray(function(err, result){ ... })
应该只是返回符合您的查询的文件。
如果你请求返回一个对象，你也可以使用Thing.findOne({ name: {$regex : search}}, function(err, val) {