MaxListenersExceededWarning when installing or creating Node.js projects on macOS

[parsasabetz]

Version

20.5.1

Platform

macOS (darwin)

Subsystem

No response

What steps will reproduce the bug?

I am getting the following warning message when I try to install or create Node.js projects on macOS:

(node:80101) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [TLSSocket]. Use emitter.setMaxListeners() to increase limit

I have updated Node.js to the latest version (V20.5.1) and npm was already up to date (V9.8.1). I'm not using any third-party tools, I simply use terminal.

The commands I get the warning after are:
npm install ...
and
npx ...

I'd appreciate if anyone can help me with this. So far i haven't noticed anything wrong in projects or installing process except the warning itself, but I don't understand why should the warning pop-up when I haven't made any changes to any configurations in NPM or node.

How often does it reproduce? Is there a required condition?

It happens every time I try to install (with NPM) or create a project (with NPX), no special condition produces it, it just comes up.

What is the expected behavior? Why is that the expected behavior?

Expected behavior is, NPM should normally just install and NPX should normally just create the project without any warnings!

What do you see instead?

The warning message before completion of install or create:

(node:80101) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [TLSSocket]. Use emitter.setMaxListeners() to increase limit

Additional information

No response

[peng-huang-ch]

I have the same issue, when I call a https request, but only occasionally.

node 20.5.1

This seems to be because the number of event listeners for TLSSocket exceeds the default max listeners.

node/lib/events.js

Line 270 in d2c7c36

let defaultMaxListeners = 10;

, so the process will emit warning

node/lib/events.js

Lines 585 to 592 in d2c7c36

	if (m > 0 && existing.length > m && !existing.warned) {
	existing.warned = true;
	// No error code for this since it is a Warning
	const w = genericNodeError(
	`Possible EventEmitter memory leak detected. ${existing.length} ${String(type)} listeners ` +
	`added to ${inspect(target, { depth: -1 })}. Use emitter.setMaxListeners() to increase limit`,
	{ name: 'MaxListenersExceededWarning', emitter: target, type: type, count: existing.length });
	process.emitWarning(w);

MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [TLSSocket]. Use emitter.setMaxListeners() to increase limit
    at _addListener (node:events:590:17)
    at TLSSocket.addListener (node:events:618:10)
    at Readable.on (node:internal/streams/readable:904:35)
    at TLSSocket._wrapHandle (node:_tls_wrap:674:8)
    at TLSSocket.reinitializeHandle (node:_tls_wrap:683:22)
    at internalConnectMultiple (node:net:1123:30)
    at Timeout.internalConnectMultipleTimeout (node:net:1687:3)
    at listOnTimeout (node:internal/timers:575:11)
    at process.processTimers (node:internal/timers:514:7)

emitter: <ref *1> TLSSocket {
    _tlsOptions: {
      allowHalfOpen: undefined,
      pipe: false,
      secureContext: [SecureContext],
      isServer: false,
      requestCert: true,
      rejectUnauthorized: true,
      session: undefined,
      ALPNProtocols: undefined,
      requestOCSP: undefined,
      enableTrace: undefined,
      pskCallback: undefined,
      highWaterMark: undefined,
      onread: undefined,
      signal: undefined
    },
    _secureEstablished: false,
    _securePending: false,
    _newSessionPending: false,
    _controlReleased: true,
    secureConnecting: true,
    _SNICallback: null,
    servername: null,
    alpnProtocol: null,
    authorized: false,
    authorizationError: null,
    encrypted: true,
    _events: [Object: null prototype] {
      close: [Array],
      end: [Array],
      newListener: [Array],
      connect: [Array],
      secure: [Function: onConnectSecure],
      session: [Function (anonymous)],
      free: [Function: onFree],
      timeout: [Array],
      agentRemove: [Function: onRemove],
      error: [Function: socketErrorListener],
      data: [Function: socketOnData],
      drain: [Function: ondrain]
    },
    _eventsCount: 12,
    connecting: true,
    _hadError: false,
    _parent: null,
    _host: 'mainnet.infura.io',
    _closeAfterHandlingError: false,
    _readableState: ReadableState {
      objectMode: false,
      highWaterMark: 16384,
      buffer: BufferList { head: null, tail: null, length: 0 },
      length: 0,
      pipes: [],
      flowing: true,
      ended: false,
      endEmitted: false,
      reading: false,
      constructed: true,
      sync: false,
      needReadable: true,
      emittedReadable: false,
      readableListening: false,
      resumeScheduled: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      destroyed: false,
      errored: null,
      closed: false,
      closeEmitted: false,
      defaultEncoding: 'utf8',
      awaitDrainWriters: null,
      multiAwaitDrain: false,
      readingMore: false,
      dataEmitted: false,
      decoder: null,
      encoding: null,
      [Symbol(kPaused)]: false
    },
    _maxListeners: undefined,
    _writableState: WritableState {
      objectMode: false,
      highWaterMark: 16384,
      finalCalled: false,
      needDrain: false,
      ending: false,
      ended: false,
      finished: false,
      destroyed: false,
      decodeStrings: false,
      defaultEncoding: 'utf8',
      length: 215,
      writing: true,
      corked: 0,
      sync: false,
      bufferProcessing: false,
      onwrite: [Function: bound onwrite],
      writecb: [Function (anonymous)],
      writelen: 215,
      afterWriteTickInfo: null,
      buffered: [],
      bufferedIndex: 0,
      allBuffers: true,
      allNoop: true,
      pendingcb: 1,
      constructed: true,
      prefinished: false,
      errorEmitted: false,
      emitClose: false,
      autoDestroy: true,
      errored: null,
      closed: false,
      closeEmitted: false,
      [Symbol(kOnFinished)]: []
    },
    allowHalfOpen: false,
    _sockname: null,
    _pendingData: [ [Object], [Object], [Object], allBuffers: false ],
    _pendingEncoding: '',
    server: undefined,
    _server: null,
    ssl: null,
    _requestCert: true,
    _rejectUnauthorized: true,
    timeout: 5000,
    parser: HTTPParser {
      '0': null,
      '1': [Function: parserOnHeaders],
      '2': [Function: parserOnHeadersComplete],
      '3': [Function: parserOnBody],
      '4': [Function: parserOnMessageComplete],
      '5': null,
      '6': null,
      _headers: [],
      _url: '',
      socket: [Circular *1],
      incoming: null,
      outgoing: [ClientRequest],
      maxHeaderPairs: 2000,
      _consumed: false,
      onIncoming: [Function: parserOnIncomingClient],
      joinDuplicateHeaders: undefined,
      [Symbol(resource_symbol)]: [HTTPClientAsyncResource]
    },
    _httpMessage: ClientRequest {
      _events: [Object: null prototype],
      _eventsCount: 2,
      _maxListeners: undefined,
      outputData: [],
      outputSize: 0,
      writable: true,
      destroyed: false,
      _last: false,
      chunkedEncoding: false,
      shouldKeepAlive: true,
      maxRequestsOnConnectionReached: false,
      _defaultKeepAlive: true,
      useChunkedEncodingByDefault: true,
      sendDate: false,
      _removedConnection: false,
      _removedContLen: false,
      _removedTE: false,
      strictContentLength: false,
      _contentLength: '60',
      _hasBody: true,
      _trailer: '',
      finished: true,
      _headerSent: true,
      _closed: false,
      socket: [Circular *1],
      _header: 'POST /v3/46bd2d5bcfe14e12b5468f9b3a95eac7 HTTP/1.1\r\n' +
        'content-type: application/json\r\n' +
        'Content-Length: 60\r\n' +
        'Host: mainnet.infura.io\r\n' +
        'Connection: keep-alive\r\n' +
        '\r\n',
      _keepAliveTimeout: 0,
      _onPendingData: [Function: nop],
      agent: [Agent],
      socketPath: undefined,
      method: 'POST',
      maxHeaderSize: undefined,
      insecureHTTPParser: undefined,
      joinDuplicateHeaders: undefined,
      path: '/v3/46bd2d5bcfe14e12b5468f9b3a95eac7',
      _ended: false,
      res: null,
      aborted: false,
      timeoutCb: [Function: emitRequestTimeout],
      upgradeOrConnect: false,
      parser: [HTTPParser],
      maxHeadersCount: null,
      reusedSocket: false,
      host: 'mainnet.infura.io',
      protocol: 'https:',
      [Symbol(kCapture)]: false,
      [Symbol(kBytesWritten)]: 0,
      [Symbol(kNeedDrain)]: false,
      [Symbol(corked)]: 0,
      [Symbol(kOutHeaders)]: [Object: null prototype],
      [Symbol(errored)]: null,
      [Symbol(kHighWaterMark)]: 16384,
      [Symbol(kRejectNonStandardBodyWrites)]: false,
      [Symbol(kUniqueHeaders)]: null
    },
    autoSelectFamilyAttemptedAddresses: [
      '34.234.166.131:443',
      '54.164.79.19:443',
      '54.174.23.177:443',
      '54.225.151.145:443',
      '3.219.184.255:443',
      '3.233.7.93:443',
      '34.204.32.68:443'
    ],
    handle: TLSWrap {
      _parent: [TCP],
      _parentWrap: null,
      _secureContext: [SecureContext],
      reading: false,
      onkeylog: [Function: onkeylog],
      onhandshakestart: {},
      onhandshakedone: [Function (anonymous)],
      onocspresponse: [Function: onocspresponse],
      onnewsession: [Function: onnewsessionclient],
      onerror: [Function: onerror],
      [Symbol(owner_symbol)]: [Circular *1]
    },
    [Symbol(alpncallback)]: null,
    [Symbol(res)]: TLSWrap {
      _parent: [TCP],
      _parentWrap: null,
      _secureContext: [SecureContext],
      reading: false,
      onkeylog: [Function: onkeylog],
      onhandshakestart: {},
      onhandshakedone: [Function (anonymous)],
      onocspresponse: [Function: onocspresponse],
      onnewsession: [Function: onnewsessionclient],
      onerror: [Function: onerror],
      [Symbol(owner_symbol)]: [Circular *1]
    },
    [Symbol(verified)]: false,
    [Symbol(pendingSession)]: null,
    [Symbol(async_id_symbol)]: 541,
    [Symbol(kHandle)]: TLSWrap {
      _parent: [TCP],
      _parentWrap: null,
      _secureContext: [SecureContext],
      reading: false,
      onkeylog: [Function: onkeylog],
      onhandshakestart: {},
      onhandshakedone: [Function (anonymous)],
      onocspresponse: [Function: onocspresponse],
      onnewsession: [Function: onnewsessionclient],
      onerror: [Function: onerror],
      [Symbol(owner_symbol)]: [Circular *1]
    },
    [Symbol(lastWriteQueueSize)]: 0,
    [Symbol(timeout)]: Timeout {
      _idleTimeout: 5000,
      _idlePrev: [Timeout],
      _idleNext: [Timeout],
      _idleStart: 1750,
      _onTimeout: [Function: bound ],
      _timerArgs: undefined,
      _repeat: null,
      _destroyed: false,
      [Symbol(refed)]: false,
      [Symbol(kHasPrimitive)]: false,
      [Symbol(asyncId)]: 83,
      [Symbol(triggerId)]: 0
    },
    [Symbol(kBuffer)]: null,
    [Symbol(kBufferCb)]: null,
    [Symbol(kBufferGen)]: null,
    [Symbol(kCapture)]: false,
    [Symbol(kSetNoDelay)]: false,
    [Symbol(kSetKeepAlive)]: false,
    [Symbol(kSetKeepAliveInitialDelay)]: 0,
    [Symbol(kBytesRead)]: 0,
    [Symbol(kBytesWritten)]: 0,
    [Symbol(connect-options)]: {
      rejectUnauthorized: true,
      ciphers: 'TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384:DHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA256:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!SRP:!CAMELLIA',
      checkServerIdentity: [Function: checkServerIdentity],
      minDHSize: 1024,
      protocol: 'https:',
      hostname: 'mainnet.infura.io',
      port: 443,
      path: null,
      method: 'POST',
      headers: [Object],
      _defaultAgent: [Agent],
      host: 'mainnet.infura.io',
      keepAlive: true,
      scheduling: 'lifo',
      timeout: 5000,
      noDelay: true,
      servername: 'mainnet.infura.io',
      _agentKey: 'mainnet.infura.io:443:::::::::::::::::::::',
      encoding: null,
      keepAliveInitialDelay: 1000
    }
  },
  type: 'close',
  count: 11
}

code

var request = require('request');
var options = {
  method: 'POST',
  url: 'https://mainnet.infura.io/v3/46bd2d5bcfe14e12b5468f9b3a95eac7',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'net_version',
    params: [],
    id: 67,
  }),
};
request(options, function (error, response) {
  if (error) throw new Error(error);
  console.log(response.body);
});

process.on('warning', (w) => {
  console.log(w);
});

[bnoordhuis]

Converted to a discussion because the problem probably lies with the projects/libraries you use (npm, request) rather than node itself. If you can reproduce using just built-in modules in a minimal way, let me know and I'll convert it back.

[MirKml]

Same here, after upgrade to node >= 20.9.0 - current LTS 🙂. It's raised when npm install is called on Linux CI. Locally on windows it's fine.
I'm waiting for @bnoordhuis mentioned fix/workaround.

As I saw mentioned PR, it's merged.
So we are waiting for new LTS v20 release.

[0xslipk]

I got this error using pnpm too. when the docker images is installing the deps throws that error.

[HenryGarcia96]

Same here. I got this error using npm install. Node version: 20.9.0 LTS. The previous command was npm install -g @angular/cli. I don't know if it previously happened, because I haven't been using NodeJs lately. The log is:

npm install
(node:10668) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [TLSSocket]. Use emitter.setMaxListeners() to increase limit
(Use node --trace-warnings ... to show where the warning was created)
npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR!
npm ERR! While resolving: @angular/core@16.2.12
npm ERR! Found: zone.js@0.14.2
npm ERR! node_modules/zone.js
npm ERR! zone.js@"~0.14.0" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer zone.js@"~0.13.0" from @angular/core@16.2.12
npm ERR! node_modules/@angular/core
npm ERR! @angular/core@"^16.1.0-rc.0" from the root project
npm ERR! peer @angular/core@"16.2.12" from @angular/animations@16.2.12
npm ERR! node_modules/@angular/animations
npm ERR! @angular/animations@"^16.1.0-rc.0" from the root project
npm ERR! 1 more (@angular/platform-browser)
npm ERR! 7 more (@angular/common, @angular/compiler, @angular/forms, ...)
npm ERR!
npm ERR! Conflicting peer dependency: zone.js@0.13.3
npm ERR! node_modules/zone.js
npm ERR! peer zone.js@"~0.13.0" from @angular/core@16.2.12
npm ERR! node_modules/@angular/core
npm ERR! @angular/core@"^16.1.0-rc.0" from the root project
npm ERR! peer @angular/core@"16.2.12" from @angular/animations@16.2.12
npm ERR! node_modules/@angular/animations
npm ERR! @angular/animations@"^16.1.0-rc.0" from the root project
npm ERR! 1 more (@angular/platform-browser)
npm ERR! 7 more (@angular/common, @angular/compiler, @angular/forms, ...)
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!
npm ERR!
npm ERR! For a full report see:
npm ERR! C:\Users\henry\AppData\Local\npm-cache_logs\2023-11-06T13_52_10_892Z-eresolve-report.txt

npm ERR! A complete log of this run can be found in: C:\Users\henry\AppData\Local\npm-cache_logs\2023-11-06T13_52_10_892Z-debug-0.log

Update
I got resolve this problem attach the label --force for download all dependencies.

[cbratschi]

Same here using npm v10.1.0 on Node.js v20.9.0.

[johnwc]

@bnoordhuis this occurs during a npm install, not when running packages/libraries from our code. I do think this needs to be returned back to being an open issue.

[mohmed-ahmed-dev]

This issue is related to node v20.x

Downgrading to node v18.x solves this issue.

[cbratschi]

Earlier v20.x versions worked fine here. Only the latest is affected.

[johnwc]

@cbratschi what earlier version did it not have an issue?

[cbratschi]

@johnwc I used these version before using nvm without any issues:

1. v20.2.0
2. v20.5.1
3. v20.6.1

Then it started: v20.9.0

[johnwc]

@cbratschi thanks, I will try it out and see if it does the same for us

[kingram6865]

Same. I see this error with node v20.9.0

[mohmed-ahmed-dev]

and return install npm , It will work without any problems

[johnwc]

What does "and return install npm" mean?

[Mosaab-Emam]

@johnwc He probably means rerun the npm install command and it should work (I can verify that it does).

[MirKml]

I think it's most likely of npm cache. Run npm install second time, npm makes much less network connections, so less or even none of MaxListenersExceededWarning messages are presented.

Downgrade is better workaround. Fix in upcoming LTS node is desired.

[Mosaab-Emam]

I don't think it's cache related, I tried clearing the cache and it didn't solve the problem, and it also affects yarn even though it manages cache independently. Downgrading is what ultimately worked.

[MirKml]

It seems that latest LTS 20.10.0 contains backported fix #50136.
Also NPM 10.2.3 is presented. So I think it's solved. Thanks