执行适当的MongoDB查询(TypeError:将循环结构转换为JSON)
执行适当的MongoDB查询(TypeError:将循环结构转换为JSON)
提问于 2016-11-10 04:53:41
我正在询问一些我已经做过多次的事情。看一看，我好像不明白。
/* 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: {$regex : search}}, function(err, val) {
if(err) throw error;
console.log(val); // returns some horrible JSON
res.send(JSON.stringify(val)); // Throws TypeError
});
})我想也许我的问题是错误的，也许是Mongo shell抛出的问题，但当我进入Mongo shell时。
use dbname
> db.booking.find({name: {$regex: "G"}})
>{ "_id" : ObjectId("58238283565e2c1940b16d48"), "name" : "Go to Lesters"}
这就是我打印val时发生的事情。
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我正在尝试获得像{ _id: ObjectId("58238283565e2c1940b16d48"), name: "Go to Lesters" }这样的东西
或者类似的东西，只要它有意义！我只是还没见过这样的东西。
我使用的是Node的Express JS框架，我只有Nodemon、Express、bodyParser和Mongo模块。没别的了！谢谢你，感谢你的爱！
回答 3
Stack Overflow用户
回答已采纳
发布于 2016-11-10 10:32:15
您正在记录的对象是Mongo游标。这有时会很有用，但只会获取您不需要的文档。
Thing.find(query).toArray(function(err, result){ ... })应该只返回与您的查询匹配的文档。
Stack Overflow用户
发布于 2016-11-13 07:00:57
如果请求返回单个对象，则还可以使用Thing.findOne({ name: {$regex : search}}, function(err, val) {
Stack Overflow用户
发布于 2018-08-31 04:29:24
您可以使用相同的语法，但需要使用.then或async await来处理promise
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/40515843
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