Applications running in Node.js will generally experience four categories of errors:
- Standard JavaScript errors such as {EvalError}, {SyntaxError}, {RangeError}, {ReferenceError}, {TypeError}, and {URIError}.
- System errors triggered by underlying operating system constraints such as attempting to open a file that does not exist or attempting to send data over a closed socket.
- User-specified errors triggered by application code.
AssertionError
s are a special class of error that can be triggered when Node.js detects an exceptional logic violation that should never occur. These are raised typically by thenode:assert
module.
All JavaScript and system errors raised by Node.js inherit from, or are instances of, the standard JavaScript {Error} class and are guaranteed to provide at least the properties available on that class.
Node.js supports several mechanisms for propagating and handling errors that
occur while an application is running. How these errors are reported and
handled depends entirely on the type of Error
and the style of the API that is
called.
All JavaScript errors are handled as exceptions that immediately generate
and throw an error using the standard JavaScript throw
mechanism. These
are handled using the try…catch
construct provided by the
JavaScript language.
// Throws with a ReferenceError because z is not defined.
try {
const m = 1;
const n = m + z;
} catch (err) {
// Handle the error here.
}
Any use of the JavaScript throw
mechanism will raise an exception that
must be handled or the Node.js process will exit immediately.
With few exceptions, Synchronous APIs (any blocking method that does not
return a {Promise} nor accept a callback
function, such as
fs.readFileSync
), will use throw
to report errors.
Errors that occur within Asynchronous APIs may be reported in multiple ways:
-
Some asynchronous methods returns a {Promise}, you should always take into account that it might be rejected. See
--unhandled-rejections
flag for how the process will react to an unhandled promise rejection.const fs = require('fs/promises'); (async () => { let data; try { data = await fs.readFile('a file that does not exist'); } catch (err) { console.error('There was an error reading the file!', err); return; } // Otherwise handle the data })();
-
Most asynchronous methods that accept a
callback
function will accept anError
object passed as the first argument to that function. If that first argument is notnull
and is an instance ofError
, then an error occurred that should be handled.const fs = require('node:fs'); fs.readFile('a file that does not exist', (err, data) => { if (err) { console.error('There was an error reading the file!', err); return; } // Otherwise handle the data });
-
When an asynchronous method is called on an object that is an
EventEmitter
, errors can be routed to that object's'error'
event.const net = require('node:net'); const connection = net.connect('localhost'); // Adding an 'error' event handler to a stream: connection.on('error', (err) => { // If the connection is reset by the server, or if it can't // connect at all, or on any sort of error encountered by // the connection, the error will be sent here. console.error(err); }); connection.pipe(process.stdout);
-
A handful of typically asynchronous methods in the Node.js API may still use the
throw
mechanism to raise exceptions that must be handled usingtry…catch
. There is no comprehensive list of such methods; please refer to the documentation of each method to determine the appropriate error handling mechanism required.
The use of the 'error'
event mechanism is most common for stream-based
and event emitter-based APIs, which themselves represent a series of
asynchronous operations over time (as opposed to a single operation that may
pass or fail).
For all EventEmitter
objects, if an 'error'
event handler is not
provided, the error will be thrown, causing the Node.js process to report an
uncaught exception and crash unless either: a handler has been registered for
the 'uncaughtException'
event, or the deprecated node:domain
module is used.
const EventEmitter = require('node:events');
const ee = new EventEmitter();
setImmediate(() => {
// This will crash the process because no 'error' event
// handler has been added.
ee.emit('error', new Error('This will crash'));
});
Errors generated in this way cannot be intercepted using try…catch
as
they are thrown after the calling code has already exited.
Developers must refer to the documentation for each method to determine exactly how errors raised by those methods are propagated.
A generic JavaScript {Error} object that does not denote any specific
circumstance of why the error occurred. Error
objects capture a "stack trace"
detailing the point in the code at which the Error
was instantiated, and may
provide a text description of the error.
All errors generated by Node.js, including all system and JavaScript errors,
will either be instances of, or inherit from, the Error
class.
message
{string}options
{Object}cause
{any} The error that caused the newly created error.
Creates a new Error
object and sets the error.message
property to the
provided text message. If an object is passed as message
, the text message
is generated by calling String(message)
. If the cause
option is provided,
it is assigned to the error.cause
property. The error.stack
property will
represent the point in the code at which new Error()
was called. Stack traces
are dependent on V8's stack trace API. Stack traces extend only to either
(a) the beginning of synchronous code execution, or (b) the number of frames
given by the property Error.stackTraceLimit
, whichever is smaller.
targetObject
{Object}constructorOpt
{Function}
Creates a .stack
property on targetObject
, which when accessed returns
a string representing the location in the code at which
Error.captureStackTrace()
was called.
const myObject = {};
Error.captureStackTrace(myObject);
myObject.stack; // Similar to `new Error().stack`
The first line of the trace will be prefixed with
${myObject.name}: ${myObject.message}
.
The optional constructorOpt
argument accepts a function. If given, all frames
above constructorOpt
, including constructorOpt
, will be omitted from the
generated stack trace.
The constructorOpt
argument is useful for hiding implementation
details of error generation from the user. For instance:
function a() {
b();
}
function b() {
c();
}
function c() {
// Create an error without stack trace to avoid calculating the stack trace twice.
const { stackTraceLimit } = Error;
Error.stackTraceLimit = 0;
const error = new Error();
Error.stackTraceLimit = stackTraceLimit;
// Capture the stack trace above function b
Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
throw error;
}
a();
- {number}
The Error.stackTraceLimit
property specifies the number of stack frames
collected by a stack trace (whether generated by new Error().stack
or
Error.captureStackTrace(obj)
).
The default value is 10
but may be set to any valid JavaScript number. Changes
will affect any stack trace captured after the value has been changed.
If set to a non-number value, or set to a negative number, stack traces will not capture any frames.
- {any}
If present, the error.cause
property is the underlying cause of the Error
.
It is used when catching an error and throwing a new one with a different
message or code in order to still have access to the original error.
The error.cause
property is typically set by calling
new Error(message, { cause })
. It is not set by the constructor if the
cause
option is not provided.
This property allows errors to be chained. When serializing Error
objects,
util.inspect()
recursively serializes error.cause
if it is set.
const cause = new Error('The remote HTTP server responded with a 500 status');
const symptom = new Error('The message failed to send', { cause });
console.log(symptom);
// Prints:
// Error: The message failed to send
// at REPL2:1:17
// at Script.runInThisContext (node:vm:130:12)
// ... 7 lines matching cause stack trace ...
// at [_line] [as _line] (node:internal/readline/interface:886:18) {
// [cause]: Error: The remote HTTP server responded with a 500 status
// at REPL1:1:15
// at Script.runInThisContext (node:vm:130:12)
// at REPLServer.defaultEval (node:repl:574:29)
// at bound (node:domain:426:15)
// at REPLServer.runBound [as eval] (node:domain:437:12)
// at REPLServer.onLine (node:repl:902:10)
// at REPLServer.emit (node:events:549:35)
// at REPLServer.emit (node:domain:482:12)
// at [_onLine] [as _onLine] (node:internal/readline/interface:425:12)
// at [_line] [as _line] (node:internal/readline/interface:886:18)
- {string}
The error.code
property is a string label that identifies the kind of error.
error.code
is the most stable way to identify an error. It will only change
between major versions of Node.js. In contrast, error.message
strings may
change between any versions of Node.js. See Node.js error codes for details
about specific codes.
- {string}
The error.message
property is the string description of the error as set by
calling new Error(message)
. The message
passed to the constructor will also
appear in the first line of the stack trace of the Error
, however changing
this property after the Error
object is created may not change the first
line of the stack trace (for example, when error.stack
is read before this
property is changed).
const err = new Error('The message');
console.error(err.message);
// Prints: The message
- {string}
The error.stack
property is a string describing the point in the code at which
the Error
was instantiated.
Error: Things keep happening!
at /home/gbusey/file.js:525:2
at Frobnicator.refrobulate (/home/gbusey/business-logic.js:424:21)
at Actor.<anonymous> (/home/gbusey/actors.js:400:8)
at increaseSynergy (/home/gbusey/actors.js:701:6)
The first line is formatted as <error class name>: <error message>
, and
is followed by a series of stack frames (each line beginning with "at ").
Each frame describes a call site within the code that lead to the error being
generated. V8 attempts to display a name for each function (by variable name,
function name, or object method name), but occasionally it will not be able to
find a suitable name. If V8 cannot determine a name for the function, only
location information will be displayed for that frame. Otherwise, the
determined function name will be displayed with location information appended
in parentheses.
Frames are only generated for JavaScript functions. If, for example, execution
synchronously passes through a C++ addon function called cheetahify
which
itself calls a JavaScript function, the frame representing the cheetahify
call
will not be present in the stack traces:
const cheetahify = require('./native-binding.node');
function makeFaster() {
// `cheetahify()` *synchronously* calls speedy.
cheetahify(function speedy() {
throw new Error('oh no!');
});
}
makeFaster();
// will throw:
// /home/gbusey/file.js:6
// throw new Error('oh no!');
// ^
// Error: oh no!
// at speedy (/home/gbusey/file.js:6:11)
// at makeFaster (/home/gbusey/file.js:5:3)
// at Object.<anonymous> (/home/gbusey/file.js:10:1)
// at Module._compile (module.js:456:26)
// at Object.Module._extensions..js (module.js:474:10)
// at Module.load (module.js:356:32)
// at Function.Module._load (module.js:312:12)
// at Function.Module.runMain (module.js:497:10)
// at startup (node.js:119:16)
// at node.js:906:3
The location information will be one of:
native
, if the frame represents a call internal to V8 (as in[].forEach
).plain-filename.js:line:column
, if the frame represents a call internal to Node.js./absolute/path/to/file.js:line:column
, if the frame represents a call in a user program (using CommonJS module system), or its dependencies.<transport-protocol>:///url/to/module/file.mjs:line:column
, if the frame represents a call in a user program (using ES module system), or its dependencies.
The string representing the stack trace is lazily generated when the
error.stack
property is accessed.
The number of frames captured by the stack trace is bounded by the smaller of
Error.stackTraceLimit
or the number of available frames on the current event
loop tick.
- Extends: {errors.Error}
Indicates the failure of an assertion. For details, see
Class: assert.AssertionError
.
- Extends: {errors.Error}
Indicates that a provided argument was not within the set or range of acceptable values for a function; whether that is a numeric range, or outside the set of options for a given function parameter.
require('node:net').connect(-1);
// Throws "RangeError: "port" option should be >= 0 and < 65536: -1"
Node.js will generate and throw RangeError
instances immediately as a form
of argument validation.
- Extends: {errors.Error}
Indicates that an attempt is being made to access a variable that is not defined. Such errors commonly indicate typos in code, or an otherwise broken program.
While client code may generate and propagate these errors, in practice, only V8 will do so.
doesNotExist;
// Throws ReferenceError, doesNotExist is not a variable in this program.
Unless an application is dynamically generating and running code,
ReferenceError
instances indicate a bug in the code or its dependencies.
- Extends: {errors.Error}
Indicates that a program is not valid JavaScript. These errors may only be
generated and propagated as a result of code evaluation. Code evaluation may
happen as a result of eval
, Function
, require
, or vm. These errors
are almost always indicative of a broken program.
try {
require('node:vm').runInThisContext('binary ! isNotOk');
} catch (err) {
// 'err' will be a SyntaxError.
}
SyntaxError
instances are unrecoverable in the context that created them –
they may only be caught by other contexts.
- Extends: {errors.Error}
Node.js generates system errors when exceptions occur within its runtime environment. These usually occur when an application violates an operating system constraint. For example, a system error will occur if an application attempts to read a file that does not exist.
address
{string} If present, the address to which a network connection failedcode
{string} The string error codedest
{string} If present, the file path destination when reporting a file system errorerrno
{number} The system-provided error numberinfo
{Object} If present, extra details about the error conditionmessage
{string} A system-provided human-readable description of the errorpath
{string} If present, the file path when reporting a file system errorport
{number} If present, the network connection port that is not availablesyscall
{string} The name of the system call that triggered the error
- {string}
If present, error.address
is a string describing the address to which a
network connection failed.
- {string}
The error.code
property is a string representing the error code.
- {string}
If present, error.dest
is the file path destination when reporting a file
system error.
- {number}
The error.errno
property is a negative number which corresponds
to the error code defined in libuv Error handling
.
On Windows the error number provided by the system will be normalized by libuv.
To get the string representation of the error code, use
util.getSystemErrorName(error.errno)
.
- {Object}
If present, error.info
is an object with details about the error condition.
- {string}
error.message
is a system-provided human-readable description of the error.
- {string}
If present, error.path
is a string containing a relevant invalid pathname.
- {number}
If present, error.port
is the network connection port that is not available.
- {string}
The error.syscall
property is a string describing the syscall that failed.
This is a list of system errors commonly-encountered when writing a Node.js
program. For a comprehensive list, see the errno
(3) man page.
-
EACCES
(Permission denied): An attempt was made to access a file in a way forbidden by its file access permissions. -
EADDRINUSE
(Address already in use): An attempt to bind a server (net
,http
, orhttps
) to a local address failed due to another server on the local system already occupying that address. -
ECONNREFUSED
(Connection refused): No connection could be made because the target machine actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host. -
ECONNRESET
(Connection reset by peer): A connection was forcibly closed by a peer. This normally results from a loss of the connection on the remote socket due to a timeout or reboot. Commonly encountered via thehttp
andnet
modules. -
EEXIST
(File exists): An existing file was the target of an operation that required that the target not exist. -
EISDIR
(Is a directory): An operation expected a file, but the given pathname was a directory. -
EMFILE
(Too many open files in system): Maximum number of file descriptors allowable on the system has been reached, and requests for another descriptor cannot be fulfilled until at least one has been closed. This is encountered when opening many files at once in parallel, especially on systems (in particular, macOS) where there is a low file descriptor limit for processes. To remedy a low limit, runulimit -n 2048
in the same shell that will run the Node.js process. -
ENOENT
(No such file or directory): Commonly raised byfs
operations to indicate that a component of the specified pathname does not exist. No entity (file or directory) could be found by the given path. -
ENOTDIR
(Not a directory): A component of the given pathname existed, but was not a directory as expected. Commonly raised byfs.readdir
. -
ENOTEMPTY
(Directory not empty): A directory with entries was the target of an operation that requires an empty directory, usuallyfs.unlink
. -
ENOTFOUND
(DNS lookup failed): Indicates a DNS failure of eitherEAI_NODATA
orEAI_NONAME
. This is not a standard POSIX error. -
EPERM
(Operation not permitted): An attempt was made to perform an operation that requires elevated privileges. -
EPIPE
(Broken pipe): A write on a pipe, socket, or FIFO for which there is no process to read the data. Commonly encountered at thenet
andhttp
layers, indicative that the remote side of the stream being written to has been closed. -
ETIMEDOUT
(Operation timed out): A connect or send request failed because the connected party did not properly respond after a period of time. Usually encountered byhttp
ornet
. Often a sign that asocket.end()
was not properly called.
- Extends {errors.Error}
Indicates that a provided argument is not an allowable type. For example,
passing a function to a parameter which expects a string would be a TypeError
.
require('node:url').parse(() => { });
// Throws TypeError, since it expected a string.
Node.js will generate and throw TypeError
instances immediately as a form
of argument validation.
A JavaScript exception is a value that is thrown as a result of an invalid
operation or as the target of a throw
statement. While it is not required
that these values are instances of Error
or classes which inherit from
Error
, all exceptions thrown by Node.js or the JavaScript runtime will be
instances of Error
.
Some exceptions are unrecoverable at the JavaScript layer. Such exceptions
will always cause the Node.js process to crash. Examples include assert()
checks or abort()
calls in the C++ layer.
Errors originating in crypto
or tls
are of class Error
, and in addition to
the standard .code
and .message
properties, may have some additional
OpenSSL-specific properties.
An array of errors that can give context to where in the OpenSSL library an error originates from.
The OpenSSL function the error originates in.
The OpenSSL library the error originates in.
A human-readable string describing the reason for the error.
Used when an operation has been aborted (typically using an AbortController
).
APIs not using AbortSignal
s typically do not raise an error with this code.
This code does not use the regular ERR_*
convention Node.js errors use in
order to be compatible with the web platform's AbortError
.
A special type of error that is triggered whenever Node.js tries to get access to a resource restricted by the Permission Model.
A function argument is being used in a way that suggests that the function
signature may be misunderstood. This is thrown by the node:assert
module when
the message
parameter in assert.throws(block, message)
matches the error
message thrown by block
because that usage suggests that the user believes
message
is the expected message rather than the message the AssertionError
will display if block
does not throw.
An iterable argument (i.e. a value that works with for...of
loops) was
required, but not provided to a Node.js API.
A special type of error that can be triggered whenever Node.js detects an
exceptional logic violation that should never occur. These are raised typically
by the node:assert
module.
An attempt was made to register something that is not a function as an
AsyncHooks
callback.
The type of an asynchronous resource was invalid. Users are also able to define their own types if using the public embedder API.
Data passed to a Brotli stream was not successfully compressed.
An invalid parameter key was passed during construction of a Brotli stream.
An attempt was made to create a Node.js Buffer
instance from addon or embedder
code, while in a JS engine Context that is not associated with a Node.js
instance. The data passed to the Buffer
method will have been released
by the time the method returns.
When encountering this error, a possible alternative to creating a Buffer
instance is to create a normal Uint8Array
, which only differs in the
prototype of the resulting object. Uint8Array
s are generally accepted in all
Node.js core APIs where Buffer
s are; they are available in all Contexts.
An operation outside the bounds of a Buffer
was attempted.
An attempt has been made to create a Buffer
larger than the maximum allowed
size.
Node.js was unable to watch for the SIGINT
signal.
A child process was closed before the parent received a reply.
Used when a child process is being forked without specifying an IPC channel.
Used when the main process is trying to read data from the child process's
STDERR/STDOUT, and the data's length is longer than the maxBuffer
option.
There was an attempt to use a MessagePort
instance in a closed
state, usually after .close()
has been called.
Console
was instantiated without stdout
stream, or Console
has a
non-writable stdout
or stderr
stream.
A class constructor was called that is not callable.
A constructor for a class was called without new
.
The vm context passed into the API is not yet initialized. This could happen when an error occurs (and is caught) during the creation of the context, for example, when the allocation fails or the maximum call stack size is reached when the context is created.
An OpenSSL engine was requested (for example, through the clientCertEngine
or
privateKeyEngine
TLS options) that is not supported by the version of OpenSSL
being used, likely due to the compile-time flag OPENSSL_NO_ENGINE
.
An invalid value for the format
argument was passed to the crypto.ECDH()
class getPublicKey()
method.
An invalid value for the key
argument has been passed to the
crypto.ECDH()
class computeSecret()
method. It means that the public
key lies outside of the elliptic curve.
An invalid crypto engine identifier was passed to
require('node:crypto').setEngine()
.
The --force-fips
command-line argument was used but there was an attempt
to enable or disable FIPS mode in the node:crypto
module.
An attempt was made to enable or disable FIPS mode, but FIPS mode was not available.
hash.digest()
was called multiple times. The hash.digest()
method must
be called no more than one time per instance of a Hash
object.
hash.update()
failed for any reason. This should rarely, if ever, happen.
The given crypto keys are incompatible with the attempted operation.
The selected public or private key encoding is incompatible with other options.
Initialization of the crypto subsystem failed.
An invalid authentication tag was provided.
An invalid counter was provided for a counter-mode cipher.
An invalid elliptic-curve was provided.
An invalid crypto digest algorithm was specified.
An invalid initialization vector was provided.
An invalid JSON Web Key was provided.
The given crypto key object's type is invalid for the attempted operation.
An invalid key length was provided.
An invalid key pair was provided.
An invalid key type was provided.
An invalid message length was provided.
Invalid scrypt algorithm parameters were provided.
A crypto method was used on an object that was in an invalid state. For
instance, calling cipher.getAuthTag()
before calling cipher.final()
.
An invalid authentication tag length was provided.
Initialization of an asynchronous crypto operation failed.
Key's Elliptic Curve is not registered for use in the JSON Web Key Elliptic Curve Registry.
Key's Asymmetric Key Type is not registered for use in the JSON Web Key Types Registry.
A crypto operation failed for an otherwise unspecified reason.
The PBKDF2 algorithm failed for unspecified reasons. OpenSSL does not provide more details and therefore neither does Node.js.
One or more crypto.scrypt()
or crypto.scryptSync()
parameters are
outside their legal range.
Node.js was compiled without scrypt
support. Not possible with the official
release binaries but can happen with custom builds, including distro builds.
A signing key
was not provided to the sign.sign()
method.
crypto.timingSafeEqual()
was called with Buffer
, TypedArray
, or
DataView
arguments of different lengths.
An unknown cipher was specified.
An unknown Diffie-Hellman group name was given. See
crypto.getDiffieHellman()
for a list of valid group names.
An attempt to invoke an unsupported crypto operation was made.
An error occurred with the debugger.
The debugger timed out waiting for the required host/port to be free.
Loading native addons has been disabled using --no-addons
.
A call to process.dlopen()
failed.
The fs.Dir
was previously closed.
A synchronous read or close call was attempted on an fs.Dir
which has
ongoing asynchronous operations.
c-ares
failed to set the DNS server.
The node:domain
module was not usable since it could not establish the
required error handling hooks, because
process.setUncaughtExceptionCaptureCallback()
had been called at an
earlier point in time.
process.setUncaughtExceptionCaptureCallback()
could not be called
because the node:domain
module has been loaded at an earlier point in time.
The stack trace is extended to include the point in time at which the
node:domain
module had been loaded.
v8.startupSnapshot.setDeserializeMainFunction()
could not be called
because it had already been called before.
Data provided to TextDecoder()
API was invalid according to the encoding
provided.
Encoding provided to TextDecoder()
API was not one of the
WHATWG Supported Encodings.
--print
cannot be used with ESM input.
Thrown when an attempt is made to recursively dispatch an event on EventTarget
.
The JS execution context is not associated with a Node.js environment. This may occur when Node.js is used as an embedded library and some hooks for the JS engine are not set up properly.
A Promise
that was callbackified via util.callbackify()
was rejected with a
falsy value.
Used when a feature that is not available to the current platform which is running Node.js is used.
An attempt was made to copy a directory to a non-directory (file, symlink,
etc.) using fs.cp()
.
An attempt was made to copy over a file that already existed with
fs.cp()
, with the force
and errorOnExist
set to true
.
When using fs.cp()
, src
or dest
pointed to an invalid path.
An error is thrown when writing to an HTTP response which does not allow contents.
Response body size doesn't match with the specified content-length header value.
An attempt was made to copy a named pipe with fs.cp()
.
An attempt was made to copy a non-directory (file, symlink, etc.) to a directory
using fs.cp()
.
An attempt was made to copy to a socket with fs.cp()
.
When using fs.cp()
, a symlink in dest
pointed to a subdirectory
of src
.
An attempt was made to copy to an unknown file type with fs.cp()
.
Path is a directory.
An attempt has been made to read a file whose size is larger than the maximum
allowed size for a Buffer
.
An invalid symlink type was passed to the fs.symlink()
or
fs.symlinkSync()
methods.
An attempt was made to add more headers after the headers had already been sent.
An invalid HTTP header value was specified.
Status code was outside the regular status code range (100-999).
The client has not sent the entire request within the allowed time.
The given ServerResponse
was already assigned a socket.
Changing the socket encoding is not allowed per RFC 7230 Section 3.
The Trailer
header was set even though the transfer encoding does not support
that.
HTTP/2 ALTSVC frames require a valid origin.
HTTP/2 ALTSVC frames are limited to a maximum of 16,382 payload bytes.
For HTTP/2 requests using the CONNECT
method, the :authority
pseudo-header
is required.
For HTTP/2 requests using the CONNECT
method, the :path
pseudo-header is
forbidden.
For HTTP/2 requests using the CONNECT
method, the :scheme
pseudo-header is
forbidden.
A non-specific HTTP/2 error has occurred.
New HTTP/2 Streams may not be opened after the Http2Session
has received a
GOAWAY
frame from the connected peer.
Multiple values were provided for an HTTP/2 header field that was required to have only a single value.
An additional headers was specified after an HTTP/2 response was initiated.
An attempt was made to send multiple response headers.
Informational HTTP status codes (1xx
) may not be set as the response status
code on HTTP/2 responses.
HTTP/1 connection specific headers are forbidden to be used in HTTP/2 requests and responses.
An invalid HTTP/2 header value was specified.
An invalid HTTP informational status code has been specified. Informational
status codes must be an integer between 100
and 199
(inclusive).
HTTP/2 ORIGIN
frames require a valid origin.
Input Buffer
and Uint8Array
instances passed to the
http2.getUnpackedSettings()
API must have a length that is a multiple of
six.
Only valid HTTP/2 pseudoheaders (:status
, :path
, :authority
, :scheme
,
and :method
) may be used.
An action was performed on an Http2Session
object that had already been
destroyed.
An invalid value has been specified for an HTTP/2 setting.
An operation was performed on a stream that had already been destroyed.
Whenever an HTTP/2 SETTINGS
frame is sent to a connected peer, the peer is
required to send an acknowledgment that it has received and applied the new
SETTINGS
. By default, a maximum number of unacknowledged SETTINGS
frames may
be sent at any given time. This error code is used when that limit has been
reached.
An attempt was made to initiate a new push stream from within a push stream. Nested push streams are not permitted.
Out of memory when using the http2session.setLocalWindowSize(windowSize)
API.
An attempt was made to directly manipulate (read, write, pause, resume, etc.) a
socket attached to an Http2Session
.
HTTP/2 ORIGIN
frames are limited to a length of 16382 bytes.
The number of streams created on a single HTTP/2 session reached the maximum limit.
A message payload was specified for an HTTP response code for which a payload is forbidden.
An HTTP/2 ping was canceled.
HTTP/2 ping payloads must be exactly 8 bytes in length.
An HTTP/2 pseudo-header has been used inappropriately. Pseudo-headers are header
key names that begin with the :
prefix.
An attempt was made to create a push stream, which had been disabled by the client.
An attempt was made to use the Http2Stream.prototype.responseWithFile()
API to
send a directory.
An attempt was made to use the Http2Stream.prototype.responseWithFile()
API to
send something other than a regular file, but offset
or length
options were
provided.
The Http2Session
closed with a non-zero error code.
The Http2Session
settings canceled.
An attempt was made to connect a Http2Session
object to a net.Socket
or
tls.TLSSocket
that had already been bound to another Http2Session
object.
An attempt was made to use the socket
property of an Http2Session
that
has already been closed.
Use of the 101
Informational status code is forbidden in HTTP/2.
An invalid HTTP status code has been specified. Status codes must be an integer
between 100
and 599
(inclusive).
An Http2Stream
was destroyed before any data was transmitted to the connected
peer.
A non-zero error code was been specified in an RST_STREAM
frame.
When setting the priority for an HTTP/2 stream, the stream may be marked as a dependency for a parent stream. This error code is used when an attempt is made to mark a stream and dependent of itself.
The number of supported custom settings (10) has been exceeded.
The limit of acceptable invalid HTTP/2 protocol frames sent by the peer,
as specified through the maxSessionInvalidFrames
option, has been exceeded.
Trailing headers have already been sent on the Http2Stream
.
The http2stream.sendTrailers()
method cannot be called until after the
'wantTrailers'
event is emitted on an Http2Stream
object. The
'wantTrailers'
event will only be emitted if the waitForTrailers
option
is set for the Http2Stream
.
http2.connect()
was passed a URL that uses any protocol other than http:
or
https:
.
An attempt was made to construct an object using a non-public constructor.
An import type
attribute was provided, but the specified module is of a
different type.
An import attribute is missing, preventing the specified module to be imported.
An import attribute is not supported by this version of Node.js.
An option pair is incompatible with each other and cannot be used at the same time.
Stability: 1 - Experimental
The --input-type
flag was used to attempt to execute a file. This flag can
only be used with input via --eval
, --print
, or STDIN
.
While using the node:inspector
module, an attempt was made to activate the
inspector when it already started to listen on a port. Use inspector.close()
before activating it on a different address.
While using the node:inspector
module, an attempt was made to connect when the
inspector was already connected.
While using the node:inspector
module, an attempt was made to use the
inspector after the session had already closed.
An error occurred while issuing a command via the node:inspector
module.
The inspector
is not active when inspector.waitForDebugger()
is called.
The node:inspector
module is not available for use.
While using the node:inspector
module, an attempt was made to use the
inspector before it was connected.
An API was called on the main thread that can only be used from the worker thread.
There was a bug in Node.js or incorrect usage of Node.js internals. To fix the error, open an issue at https://github.com/nodejs/node/issues.
The provided address family is not understood by the Node.js API.
An argument of the wrong type was passed to a Node.js API.
An invalid or unsupported value was passed for a given argument.
An invalid asyncId
or triggerAsyncId
was passed using AsyncHooks
. An id
less than -1 should never happen.
A swap was performed on a Buffer
but its size was not compatible with the
operation.
Invalid characters were detected in headers.
A cursor on a given stream cannot be moved to a specified row without a specified column.
A file descriptor ('fd') was not valid (e.g. it was a negative value).
A file descriptor ('fd') type was not valid.
A Node.js API that consumes file:
URLs (such as certain functions in the
fs
module) encountered a file URL with an incompatible host. This
situation can only occur on Unix-like systems where only localhost
or an empty
host is supported.
A Node.js API that consumes file:
URLs (such as certain functions in the
fs
module) encountered a file URL with an incompatible path. The exact
semantics for determining whether a path can be used is platform-dependent.
An attempt was made to send an unsupported "handle" over an IPC communication
channel to a child process. See subprocess.send()
and process.send()
for more information.
An invalid HTTP token was supplied.
An IP address is not valid.
The syntax of a MIME is not valid.
An attempt was made to load a module that does not exist or was otherwise not valid.
The imported module string is an invalid URL, package name, or package subpath specifier.
An error occurred while setting an invalid attribute on the property of an object.
An invalid package.json
file failed parsing.
The package.json
"exports"
field contains an invalid target mapping
value for the attempted module resolution.
While using the Performance Timing API (perf_hooks
), a performance mark is
invalid.
An invalid options.protocol
was passed to http.request()
.
Both breakEvalOnSigint
and eval
options were set in the REPL
config,
which is not supported.
The input may not be used in the REPL
. The conditions under which this
error is used are described in the REPL
documentation.
Thrown in case a function option does not provide a valid value for one of its returned object properties on execution.
Thrown in case a function option does not provide an expected value type for one of its returned object properties on execution.
Thrown in case a function option does not return an expected value type on execution, such as when a function is expected to return a promise.
Indicates that an operation cannot be completed due to an invalid state. For instance, an object may have already been destroyed, or may be performing another operation.
A Buffer
, TypedArray
, DataView
, or string
was provided as stdio input to
an asynchronous fork. See the documentation for the child_process
module
for more information.
A Node.js API function was called with an incompatible this
value.
const urlSearchParams = new URLSearchParams('foo=bar&baz=new');
const buf = Buffer.alloc(1);
urlSearchParams.has.call(buf, 'foo');
// Throws a TypeError with code 'ERR_INVALID_THIS'
An element in the iterable
provided to the WHATWG
URLSearchParams
constructor did not
represent a [name, value]
tuple – that is, if an element is not iterable, or
does not consist of exactly two elements.
An invalid URI was passed.
An invalid URL was passed to the WHATWG URL
constructor or the legacy url.parse()
to be parsed.
The thrown error object typically has an additional property 'input'
that
contains the URL that failed to parse.
An attempt was made to use a URL of an incompatible scheme (protocol) for a
specific purpose. It is only used in the WHATWG URL API support in the
fs
module (which only accepts URLs with 'file'
scheme), but may be used
in other Node.js APIs as well in the future.
An attempt was made to use an IPC communication channel that was already closed.
An attempt was made to disconnect an IPC communication channel that was already
disconnected. See the documentation for the child_process
module
for more information.
An attempt was made to create a child Node.js process using more than one IPC
communication channel. See the documentation for the child_process
module
for more information.
An attempt was made to open an IPC communication channel with a synchronously
forked Node.js process. See the documentation for the child_process
module
for more information.
An ESM loader hook returned without calling next()
and without explicitly
signaling a short circuit.
An attempt was made to load a resource, but the resource did not match the integrity defined by the policy manifest. See the documentation for policy manifests for more information.
An attempt was made to load a resource, but the resource was not listed as a dependency from the location that attempted to load it. See the documentation for policy manifests for more information.
An attempt was made to load a policy manifest, but the manifest had multiple entries for a resource which did not match each other. Update the manifest entries to match in order to resolve this error. See the documentation for policy manifests for more information.
A policy manifest resource had an invalid value for one of its fields. Update the manifest entry to match in order to resolve this error. See the documentation for policy manifests for more information.
A policy manifest resource had an invalid value for one of its dependency mappings. Update the manifest entry to match to resolve this error. See the documentation for policy manifests for more information.
An attempt was made to load a policy manifest, but the manifest was unable to be parsed. See the documentation for policy manifests for more information.
An attempt was made to read from a policy manifest, but the manifest initialization has not yet taken place. This is likely a bug in Node.js.
A policy manifest was loaded, but had an unknown value for its "onerror" behavior. See the documentation for policy manifests for more information.
An attempt was made to allocate memory (usually in the C++ layer) but it failed.
A message posted to a MessagePort
could not be deserialized in the target
vm Context
. Not all Node.js objects can be successfully instantiated in
any context at this time, and attempting to transfer them using postMessage()
can fail on the receiving side in that case.
A method is required but not implemented.
A required argument of a Node.js API was not passed. This is only used for
strict compliance with the API specification (which in some cases may accept
func(undefined)
but not func()
). In most native Node.js APIs,
func(undefined)
and func()
are treated identically, and the
ERR_INVALID_ARG_TYPE
error code may be used instead.
For APIs that accept options objects, some options might be mandatory. This code is thrown if a required option is missing.
An attempt was made to read an encrypted key without specifying a passphrase.
The V8 platform used by this instance of Node.js does not support creating Workers. This is caused by lack of embedder support for Workers. In particular, this error will not occur with standard builds of Node.js.
A module file could not be resolved by the ECMAScript modules loader while
attempting an import
operation or when loading the program entry point.
A callback was called more than once.
A callback is almost always meant to only be called once as the query can either be fulfilled or rejected but not both at the same time. The latter would be possible by calling a callback more than once.
While using Node-API
, a constructor passed was not a function.
While calling napi_create_dataview()
, a given offset
was outside the bounds
of the dataview or offset + length
was larger than a length of given buffer
.
While calling napi_create_typedarray()
, the provided offset
was not a
multiple of the element size.
While calling napi_create_typedarray()
, (length * size_of_element) + byte_offset
was larger than the length of given buffer
.
An error occurred while invoking the JavaScript portion of the thread-safe function.
An error occurred while attempting to retrieve the JavaScript undefined
value.
On the main thread, values are removed from the queue associated with the thread-safe function in an idle loop. This error indicates that an error has occurred when attempting to start the loop.
Once no more items are left in the queue, the idle loop must be suspended. This error indicates that the idle loop has failed to stop.
An attempt was made to use operations that can only be used when building V8 startup snapshot even though Node.js isn't building one.
The operation cannot be performed when it's not in a single-executable application.
An attempt was made to perform operations that are not supported when building a startup snapshot.
An attempt was made to use crypto features while Node.js was not compiled with OpenSSL crypto support.
An attempt was made to use features that require ICU, but Node.js was not compiled with ICU support.
A non-context-aware native addon was loaded in a process that disallows them.
A given value is out of the accepted range.
The package.json
"imports"
field does not define the given internal
package specifier mapping.
The package.json
"exports"
field does not export the requested subpath.
Because exports are encapsulated, private internal modules that are not exported
cannot be imported through the package resolution, unless using an absolute URL.
When strict
set to true
, thrown by util.parseArgs()
if a {boolean}
value is provided for an option of type {string}, or if a {string}
value is provided for an option of type {boolean}.
Thrown by util.parseArgs()
, when a positional argument is provided and
allowPositionals
is set to false
.
When strict
set to true
, thrown by util.parseArgs()
if an argument
is not configured in options
.
An invalid timestamp value was provided for a performance mark or measure.
Invalid options were provided for a performance measure.
Accessing Object.prototype.__proto__
has been forbidden using
--disable-proto=throw
. Object.getPrototypeOf
and
Object.setPrototypeOf
should be used to get and set the prototype of an
object.
Stability: 1 - Experimental
An attempt was made to require()
an ES Module.
Script execution was interrupted by SIGINT
(For
example, Ctrl+C was pressed.)
Script execution timed out, possibly due to bugs in the script being executed.
The server.listen()
method was called while a net.Server
was already
listening. This applies to all instances of net.Server
, including HTTP, HTTPS,
and HTTP/2 Server
instances.
The server.close()
method was called when a net.Server
was not
running. This applies to all instances of net.Server
, including HTTP, HTTPS,
and HTTP/2 Server
instances.
A key was passed to single executable application APIs to identify an asset, but no match could be found.
An attempt was made to bind a socket that has already been bound.
An invalid (negative) size was passed for either the recvBufferSize
or
sendBufferSize
options in dgram.createSocket()
.
An API function expecting a port >= 0 and < 65536 received an invalid value.
An API function expecting a socket type (udp4
or udp6
) received an invalid
value.
While using dgram.createSocket()
, the size of the receive or send Buffer
could not be determined.
An attempt was made to operate on an already closed socket.
When calling net.Socket.write()
on a connecting socket and the socket was
closed before the connection was established.
The socket was unable to connect to any address returned by the DNS within the allowed timeout when using the family autoselection algorithm.
A dgram.connect()
call was made on an already connected socket.
A dgram.disconnect()
or dgram.remoteAddress()
call was made on a
disconnected socket.
A call was made and the UDP subsystem was not running.
A string was provided for a Subresource Integrity check, but was unable to be parsed. Check the format of integrity attributes by looking at the Subresource Integrity specification.
A stream method was called that cannot complete because the stream was finished.
An attempt was made to call stream.pipe()
on a Writable
stream.
A stream method was called that cannot complete because the stream was
destroyed using stream.destroy()
.
An attempt was made to call stream.write()
with a null
chunk.
An error returned by stream.finished()
and stream.pipeline()
, when a stream
or a pipeline ends non gracefully with no explicit error.
An attempt was made to call stream.push()
after a null
(EOF) had been
pushed to the stream.
An attempt was made to call stream.unshift()
after the 'end'
event was
emitted.
Prevents an abort if a string decoder was set on the Socket or if the decoder
is in objectMode
.
const Socket = require('node:net').Socket;
const instance = new Socket();
instance.setEncoding('utf8');
An attempt was made to call stream.write()
after stream.end()
has been
called.
An attempt has been made to create a string longer than the maximum allowed length.
An artificial error object used to capture the call stack for diagnostic reports.
An unspecified or non-specific system error has occurred within the Node.js
process. The error object will have an err.info
object property with
additional details.
An error representing a failing lexer state.
An error representing a failing parser state. Additional information about
the token causing the error is available via the cause
property.
This error represents a failed TAP validation.
This error represents a failed test. Additional information about the failure
is available via the cause
property. The failureType
property specifies
what the test was doing when the failure occurred.
This error is thrown when an ALPNCallback
returns a value that is not in the
list of ALPN protocols offered by the client.
This error is thrown when creating a TLSServer
if the TLS options include
both ALPNProtocols
and ALPNCallback
. These options are mutually exclusive.
This error is thrown by checkServerIdentity
if a user-supplied
subjectaltname
property violates encoding rules. Certificate objects produced
by Node.js itself always comply with encoding rules and will never cause
this error.
While using TLS, the host name/IP of the peer did not match any of the
subjectAltNames
in its certificate.
While using TLS, the parameter offered for the Diffie-Hellman (DH
)
key-agreement protocol is too small. By default, the key length must be greater
than or equal to 1024 bits to avoid vulnerabilities, even though it is strongly
recommended to use 2048 bits or larger for stronger security.
A TLS/SSL handshake timed out. In this case, the server must also abort the connection.
The context must be a SecureContext
.
The specified secureProtocol
method is invalid. It is either unknown, or
disabled because it is insecure.
Valid TLS protocol versions are 'TLSv1'
, 'TLSv1.1'
, or 'TLSv1.2'
.
The TLS socket must be connected and securely established. Ensure the 'secure' event is emitted before continuing.
Attempting to set a TLS protocol minVersion
or maxVersion
conflicts with an
attempt to set the secureProtocol
explicitly. Use one mechanism or the other.
Failed to set PSK identity hint. Hint may be too long.
An attempt was made to renegotiate TLS on a socket instance with renegotiation disabled.
While using TLS, the server.addContext()
method was called without providing
a host name in the first parameter.
An excessive amount of TLS renegotiations is detected, which is a potential vector for denial-of-service attacks.
An attempt was made to issue Server Name Indication from a TLS server-side socket, which is only valid from a client.
The trace_events.createTracing()
method requires at least one trace event
category.
The node:trace_events
module could not be loaded because Node.js was compiled
with the --without-v8-platform
flag.
A Transform
stream finished while it was still transforming.
A Transform
stream finished with data still in the write buffer.
The initialization of a TTY failed due to a system error.
Function was called within a process.on('exit')
handler that shouldn't be
called within process.on('exit')
handler.
process.setUncaughtExceptionCaptureCallback()
was called twice,
without first resetting the callback to null
.
This error is designed to prevent accidentally overwriting a callback registered from another module.
A string that contained unescaped characters was received.
An unhandled error occurred (for instance, when an 'error'
event is emitted
by an EventEmitter
but an 'error'
handler is not registered).
Used to identify a specific kind of internal Node.js error that should not typically be triggered by user code. Instances of this error point to an internal bug within the Node.js binary itself.
A Unix group or user identifier that does not exist was passed.
An invalid or unknown encoding option was passed to an API.
Stability: 1 - Experimental
An attempt was made to load a module with an unknown or unsupported file extension.
Stability: 1 - Experimental
An attempt was made to load a module with an unknown or unsupported format.
An invalid or unknown process signal was passed to an API expecting a valid
signal (such as subprocess.kill()
).
import
a directory URL is unsupported. Instead,
self-reference a package using its name and define a custom subpath in
the "exports"
field of the package.json
file.
import './'; // unsupported
import './index.js'; // supported
import 'package-name'; // supported
import
with URL schemes other than file
and data
is unsupported.
An attempt was made to resolve an invalid module referrer. This can happen when
importing or calling import.meta.resolve()
with either:
- a bare specifier that is not a builtin module from a module whose URL scheme
is not
file
. - a relative URL from a module whose URL scheme is not a special scheme.
try {
// Trying to import the package 'bare-specifier' from a `data:` URL module:
await import('data:text/javascript,import "bare-specifier"');
} catch (e) {
console.log(e.code); // ERR_UNSUPPORTED_RESOLVE_REQUEST
}
Stability: 1 - Experimental
An attempt was made to use something that was already closed.
While using the Performance Timing API (perf_hooks
), no valid performance
entry types are found.
A dynamic import callback was invoked without --experimental-vm-modules
.
A dynamic import callback was not specified.
The module attempted to be linked is not eligible for linking, because of one of the following reasons:
- It has already been linked (
linkingStatus
is'linked'
) - It is being linked (
linkingStatus
is'linking'
) - Linking has failed for this module (
linkingStatus
is'errored'
)
The cachedData
option passed to a module constructor is invalid.
Cached data cannot be created for modules which have already been evaluated.
The module being returned from the linker function is from a different context than the parent module. Linked modules must share the same context.
The module was unable to be linked due to a failure.
The fulfilled value of a linking promise is not a vm.Module
object.
The current module's status does not allow for this operation. The specific meaning of the error depends on the specific function.
The WASI instance has already started.
The WASI instance has not been started.
The Response
that has been passed to WebAssembly.compileStreaming
or to
WebAssembly.instantiateStreaming
is not a valid WebAssembly response.
The Worker
initialization failed.
The execArgv
option passed to the Worker
constructor contains
invalid flags.
An operation failed because the Worker
instance is not currently running.
The Worker
instance terminated because it reached its memory limit.
The path for the main script of a worker is neither an absolute path
nor a relative path starting with ./
or ../
.
All attempts at serializing an uncaught exception from a worker thread failed.
The requested functionality is not supported in worker threads.
Creation of a zlib
object failed due to incorrect configuration.
Too much HTTP header data was received. In order to protect against malicious or
malconfigured clients, if more than 8 KiB of HTTP header data is received then
HTTP parsing will abort without a request or response object being created, and
an Error
with this code will be emitted.
Server is sending both a Content-Length
header and Transfer-Encoding: chunked
.
Transfer-Encoding: chunked
allows the server to maintain an HTTP persistent
connection for dynamically generated content.
In this case, the Content-Length
HTTP header cannot be used.
Use Content-Length
or Transfer-Encoding: chunked
.
A module file could not be resolved by the CommonJS modules loader while
attempting a require()
operation or when loading the program entry point.
Stability: 0 - Deprecated. These error codes are either inconsistent, or have been removed.
The value passed to postMessage()
contained an object that is not supported
for transferring.
The UTF-16 encoding was used with hash.digest()
. While the
hash.digest()
method does allow an encoding
argument to be passed in,
causing the method to return a string rather than a Buffer
, the UTF-16
encoding (e.g. ucs
or utf16le
) is not supported.
Used when a failure occurs sending an individual frame on the HTTP/2 session.
Used when an HTTP/2 Headers Object is expected.
Used when a required header is missing in an HTTP/2 message.
HTTP/2 informational headers must only be sent prior to calling the
Http2Stream.prototype.respond()
method.
Used when an action has been performed on an HTTP/2 Stream that has already been closed.
Used when an invalid character is found in an HTTP response status message (reason phrase).
A given index was out of the accepted range (e.g. negative offsets).
An invalid or unexpected value was passed in an options object.
An invalid or unknown file encoding was passed.
An invalid transfer object was passed to postMessage()
.
An import assertion has failed, preventing the specified module to be imported.
An import assertion is missing, preventing the specified module to be imported.
An import attribute is not supported by this version of Node.js.
This error code was replaced by ERR_MISSING_TRANSFERABLE_IN_TRANSFER_LIST
in Node.js v15.0.0, because it is no longer accurate as other types of
transferable objects also exist now.
An object that needs to be explicitly listed in the transferList
argument
is in the object passed to a postMessage()
call, but is not provided
in the transferList
for that call. Usually, this is a MessagePort
.
In Node.js versions prior to v15.0.0, the error code being used here was
ERR_MISSING_MESSAGE_PORT_IN_TRANSFER_LIST
. However, the set of
transferable object types has been expanded to cover more types than
MessagePort
.
Used by the Node-API
when Constructor.prototype
is not an object.
Stability: 1 - Experimental
Response was received but was invalid when importing a module over the network.
Stability: 1 - Experimental
A network module attempted to load another module that it is not allowed to load. Likely this restriction is for security reasons.
A Node.js API was called in an unsupported manner, such as
Buffer.write(string, encoding, offset[, length])
.
An operation failed. This is typically used to signal the general failure of an asynchronous operation.
Used generically to identify that an operation caused an out of memory condition.
The node:repl
module was unable to parse data from the REPL history file.
Data could not be sent on a socket.
An attempt was made to close the process.stderr
stream. By design, Node.js
does not allow stdout
or stderr
streams to be closed by user code.
An attempt was made to close the process.stdout
stream. By design, Node.js
does not allow stdout
or stderr
streams to be closed by user code.
Used when an attempt is made to use a readable stream that has not implemented
readable._read()
.
Used when a TLS renegotiation request has failed in a non-specific way.
A SharedArrayBuffer
whose memory is not managed by the JavaScript engine
or by Node.js was encountered during serialization. Such a SharedArrayBuffer
cannot be serialized.
This can only happen when native addons create SharedArrayBuffer
s in
"externalized" mode, or put existing SharedArrayBuffer
into externalized mode.
An attempt was made to launch a Node.js process with an unknown stdin
file
type. This error is usually an indication of a bug within Node.js itself,
although it is possible for user code to trigger it.
An attempt was made to launch a Node.js process with an unknown stdout
or
stderr
file type. This error is usually an indication of a bug within Node.js
itself, although it is possible for user code to trigger it.
The V8 BreakIterator
API was used but the full ICU data set is not installed.
Used when a given value is out of the accepted range.
The module must be successfully linked before instantiation.
The linker function returned a module for which linking has failed.
The pathname used for the main script of a worker has an unknown file extension.
Used when an attempt is made to use a zlib
object after it has already been
closed.
The native call from process.cpuUsage
could not be processed.