- Assertion Testing
- Async Hooks
- Buffer
- C++ Addons
- C/C++ Addons - N-API
- Child Processes
- Cluster
- Command Line Options
- Console
- Crypto
- Debugger
- Deprecated APIs
- DNS
- Domain
- ECMAScript Modules
- Errors
- Events
- File System
- Globals
- HTTP
- HTTP/2
- HTTPS
- Inspector
- Internationalization
- Modules
- Net
- OS
- Path
- Performance Hooks
- Process
- Punycode
- Query Strings
- Readline
- REPL
- Stream
- String Decoder
- Timers
- TLS/SSL
- Trace Events
- TTY
- UDP/Datagram
- URL
- Utilities
- V8
- VM
- Worker Threads
- ZLIB
Node.js v10.13.0-rc.1 Documentation
Table of Contents
-
- Class: AssertionError
- Class: RangeError
- Class: ReferenceError
- Class: SyntaxError
- Class: TypeError
- Exceptions vs. Errors
-
- ERR_AMBIGUOUS_ARGUMENT
- ERR_ARG_NOT_ITERABLE
- ERR_ASSERTION
- ERR_ASYNC_CALLBACK
- ERR_ASYNC_TYPE
- ERR_BUFFER_OUT_OF_BOUNDS
- ERR_BUFFER_TOO_LARGE
- ERR_CANNOT_TRANSFER_OBJECT
- ERR_CANNOT_WATCH_SIGINT
- ERR_CHILD_CLOSED_BEFORE_REPLY
- ERR_CHILD_PROCESS_IPC_REQUIRED
- ERR_CHILD_PROCESS_STDIO_MAXBUFFER
- ERR_CLOSED_MESSAGE_PORT
- ERR_CONSOLE_WRITABLE_STREAM
- ERR_CONSTRUCT_CALL_REQUIRED
- ERR_CPU_USAGE
- ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED
- ERR_CRYPTO_ECDH_INVALID_FORMAT
- ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY
- ERR_CRYPTO_ENGINE_UNKNOWN
- ERR_CRYPTO_FIPS_FORCED
- ERR_CRYPTO_FIPS_UNAVAILABLE
- ERR_CRYPTO_HASH_DIGEST_NO_UTF16
- ERR_CRYPTO_HASH_FINALIZED
- ERR_CRYPTO_HASH_UPDATE_FAILED
- ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS
- ERR_CRYPTO_INVALID_DIGEST
- ERR_CRYPTO_INVALID_STATE
- ERR_CRYPTO_PBKDF2_ERROR
- ERR_CRYPTO_SCRYPT_INVALID_PARAMETER
- ERR_CRYPTO_SCRYPT_NOT_SUPPORTED
- ERR_CRYPTO_SIGN_KEY_REQUIRED
- ERR_CRYPTO_TIMING_SAFE_EQUAL_LENGTH
- ERR_DNS_SET_SERVERS_FAILED
- ERR_DOMAIN_CALLBACK_NOT_AVAILABLE
- ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE
- ERR_ENCODING_INVALID_ENCODED_DATA
- ERR_ENCODING_NOT_SUPPORTED
- ERR_FALSY_VALUE_REJECTION
- ERR_FS_FILE_TOO_LARGE
- ERR_FS_INVALID_SYMLINK_TYPE
- ERR_HTTP_HEADERS_SENT
- ERR_HTTP_INVALID_HEADER_VALUE
- ERR_HTTP_INVALID_STATUS_CODE
- ERR_HTTP_TRAILER_INVALID
- ERR_HTTP2_ALTSVC_INVALID_ORIGIN
- ERR_HTTP2_ALTSVC_LENGTH
- ERR_HTTP2_CONNECT_AUTHORITY
- ERR_HTTP2_CONNECT_PATH
- ERR_HTTP2_CONNECT_SCHEME
- ERR_HTTP2_ERROR
- ERR_HTTP2_GOAWAY_SESSION
- ERR_HTTP2_HEADERS_AFTER_RESPOND
- ERR_HTTP2_HEADERS_SENT
- ERR_HTTP2_HEADER_SINGLE_VALUE
- ERR_HTTP2_INFO_STATUS_NOT_ALLOWED
- ERR_HTTP2_INVALID_CONNECTION_HEADERS
- ERR_HTTP2_INVALID_HEADER_VALUE
- ERR_HTTP2_INVALID_INFO_STATUS
- ERR_HTTP2_INVALID_ORIGIN
- ERR_HTTP2_INVALID_PACKED_SETTINGS_LENGTH
- ERR_HTTP2_INVALID_PSEUDOHEADER
- ERR_HTTP2_INVALID_SESSION
- ERR_HTTP2_INVALID_SETTING_VALUE
- ERR_HTTP2_INVALID_STREAM
- ERR_HTTP2_MAX_PENDING_SETTINGS_ACK
- ERR_HTTP2_NESTED_PUSH
- ERR_HTTP2_NO_SOCKET_MANIPULATION
- ERR_HTTP2_ORIGIN_LENGTH
- ERR_HTTP2_OUT_OF_STREAMS
- ERR_HTTP2_PAYLOAD_FORBIDDEN
- ERR_HTTP2_PING_CANCEL
- ERR_HTTP2_PING_LENGTH
- ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED
- ERR_HTTP2_PUSH_DISABLED
- ERR_HTTP2_SEND_FILE
- ERR_HTTP2_SEND_FILE_NOSEEK
- ERR_HTTP2_SESSION_ERROR
- ERR_HTTP2_SETTINGS_CANCEL
- ERR_HTTP2_SOCKET_BOUND
- ERR_HTTP2_SOCKET_UNBOUND
- ERR_HTTP2_STATUS_101
- ERR_HTTP2_STATUS_INVALID
- ERR_HTTP2_STREAM_CANCEL
- ERR_HTTP2_STREAM_ERROR
- ERR_HTTP2_STREAM_SELF_DEPENDENCY
- ERR_HTTP2_TRAILERS_ALREADY_SENT
- ERR_HTTP2_TRAILERS_NOT_READY
- ERR_HTTP2_UNSUPPORTED_PROTOCOL
- ERR_INDEX_OUT_OF_RANGE
- ERR_INSPECTOR_ALREADY_CONNECTED
- ERR_INSPECTOR_CLOSED
- ERR_INSPECTOR_NOT_AVAILABLE
- ERR_INSPECTOR_NOT_CONNECTED
- ERR_INVALID_ADDRESS_FAMILY
- ERR_INVALID_ARG_TYPE
- ERR_INVALID_ARG_VALUE
- ERR_INVALID_ARRAY_LENGTH
- ERR_INVALID_ASYNC_ID
- ERR_INVALID_BUFFER_SIZE
- ERR_INVALID_CALLBACK
- ERR_INVALID_CHAR
- ERR_INVALID_CURSOR_POS
- ERR_INVALID_DOMAIN_NAME
- ERR_INVALID_FD
- ERR_INVALID_FD_TYPE
- ERR_INVALID_FILE_URL_HOST
- ERR_INVALID_FILE_URL_PATH
- ERR_INVALID_HANDLE_TYPE
- ERR_INVALID_HTTP_TOKEN
- ERR_INVALID_IP_ADDRESS
- ERR_INVALID_OPT_VALUE
- ERR_INVALID_OPT_VALUE_ENCODING
- ERR_INVALID_PERFORMANCE_MARK
- ERR_INVALID_PROTOCOL
- ERR_INVALID_REPL_EVAL_CONFIG
- ERR_INVALID_RETURN_PROPERTY
- ERR_INVALID_RETURN_PROPERTY_VALUE
- ERR_INVALID_RETURN_VALUE
- ERR_INVALID_SYNC_FORK_INPUT
- ERR_INVALID_THIS
- ERR_INVALID_TRANSFER_OBJECT
- ERR_INVALID_TUPLE
- ERR_INVALID_URI
- ERR_INVALID_URL
- ERR_INVALID_URL_SCHEME
- ERR_IPC_CHANNEL_CLOSED
- ERR_IPC_DISCONNECTED
- ERR_IPC_ONE_PIPE
- ERR_IPC_SYNC_FORK
- ERR_MEMORY_ALLOCATION_FAILED
- ERR_METHOD_NOT_IMPLEMENTED
- ERR_MISSING_ARGS
- ERR_MISSING_DYNAMIC_INSTANTIATE_HOOK
- ERR_MISSING_MESSAGE_PORT_IN_TRANSFER_LIST
- ERR_MISSING_MODULE
- ERR_MISSING_PLATFORM_FOR_WORKER
- ERR_MODULE_RESOLUTION_LEGACY
- ERR_MULTIPLE_CALLBACK
- ERR_NAPI_CONS_FUNCTION
- ERR_NAPI_INVALID_DATAVIEW_ARGS
- ERR_NAPI_INVALID_TYPEDARRAY_ALIGNMENT
- ERR_NAPI_INVALID_TYPEDARRAY_LENGTH
- ERR_NAPI_TSFN_CALL_JS
- ERR_NAPI_TSFN_GET_UNDEFINED
- ERR_NAPI_TSFN_START_IDLE_LOOP
- ERR_NAPI_TSFN_STOP_IDLE_LOOP
- ERR_NO_CRYPTO
- ERR_NO_ICU
- ERR_NO_LONGER_SUPPORTED
- ERR_OUT_OF_RANGE
- ERR_REQUIRE_ESM
- ERR_SCRIPT_EXECUTION_INTERRUPTED
- ERR_SERVER_ALREADY_LISTEN
- ERR_SERVER_NOT_RUNNING
- ERR_SOCKET_ALREADY_BOUND
- ERR_SOCKET_BAD_BUFFER_SIZE
- ERR_SOCKET_BAD_PORT
- ERR_SOCKET_BAD_TYPE
- ERR_SOCKET_BUFFER_SIZE
- ERR_SOCKET_CANNOT_SEND
- ERR_SOCKET_CLOSED
- ERR_SOCKET_DGRAM_NOT_RUNNING
- ERR_STREAM_CANNOT_PIPE
- ERR_STREAM_DESTROYED
- ERR_STREAM_NULL_VALUES
- ERR_STREAM_PREMATURE_CLOSE
- ERR_STREAM_PUSH_AFTER_EOF
- ERR_STREAM_UNSHIFT_AFTER_END_EVENT
- ERR_STREAM_WRAP
- ERR_STREAM_WRITE_AFTER_END
- ERR_STRING_TOO_LONG
- ERR_SYSTEM_ERROR
- ERR_TLS_CERT_ALTNAME_INVALID
- ERR_TLS_DH_PARAM_SIZE
- ERR_TLS_HANDSHAKE_TIMEOUT
- ERR_TLS_RENEGOTIATE
- ERR_TLS_RENEGOTIATION_DISABLED
- ERR_TLS_REQUIRED_SERVER_NAME
- ERR_TLS_SESSION_ATTACK
- ERR_TLS_SNI_FROM_SERVER
- ERR_TRACE_EVENTS_CATEGORY_REQUIRED
- ERR_TRACE_EVENTS_UNAVAILABLE
- ERR_TRANSFERRING_EXTERNALIZED_SHAREDARRAYBUFFER
- ERR_TRANSFORM_ALREADY_TRANSFORMING
- ERR_TRANSFORM_WITH_LENGTH_0
- ERR_TTY_INIT_FAILED
- ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET
- ERR_UNESCAPED_CHARACTERS
- ERR_UNHANDLED_ERROR
- ERR_UNKNOWN_BUILTIN_MODULE
- ERR_UNKNOWN_ENCODING
- ERR_UNKNOWN_FILE_EXTENSION
- ERR_UNKNOWN_MODULE_FORMAT
- ERR_UNKNOWN_SIGNAL
- ERR_UNKNOWN_STDIN_TYPE
- ERR_UNKNOWN_STREAM_TYPE
- ERR_V8BREAKITERATOR
- ERR_VALID_PERFORMANCE_ENTRY_TYPE
- ERR_VM_MODULE_ALREADY_LINKED
- ERR_VM_MODULE_DIFFERENT_CONTEXT
- ERR_VM_MODULE_LINKING_ERRORED
- ERR_VM_MODULE_NOT_LINKED
- ERR_VM_MODULE_NOT_MODULE
- ERR_VM_MODULE_STATUS
- ERR_WORKER_PATH
- ERR_WORKER_UNSERIALIZABLE_ERROR
- ERR_WORKER_UNSUPPORTED_EXTENSION
- ERR_ZLIB_INITIALIZATION_FAILED
- MODULE_NOT_FOUND
-
- ERR_HTTP2_FRAME_ERROR
- ERR_HTTP2_HEADERS_OBJECT
- ERR_HTTP2_HEADER_REQUIRED
- ERR_HTTP2_INFO_HEADERS_AFTER_RESPOND
- ERR_HTTP2_STREAM_CLOSED
- ERR_HTTP_INVALID_CHAR
- ERR_NAPI_CONS_PROTOTYPE_OBJECT
- ERR_OUTOFMEMORY
- ERR_PARSE_HISTORY_DATA
- ERR_STDERR_CLOSE
- ERR_STDOUT_CLOSE
- ERR_STREAM_READ_NOT_IMPLEMENTED
- ERR_TLS_RENEGOTIATION_FAILED
- ERR_UNKNOWN_BUILTIN_MODULE
- ERR_VALUE_OUT_OF_RANGE
- ERR_ZLIB_BINDING_CLOSED
Errors#
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 theassert
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.
Error Propagation and Interception#
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 undefined
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 using try…catch
or the Node.js process will exit
immediately.
With few exceptions, Synchronous APIs (any blocking method that does not
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:
- 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('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('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: The domain
module is
used appropriately or a handler has been registered for the
'uncaughtException'
event.
const EventEmitter = require('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.
Error-first callbacks#
Most asynchronous methods exposed by the Node.js core API follow an idiomatic
pattern referred to as an error-first callback. With this pattern, a callback
function is passed to the method as an argument. When the operation either
completes or an error is raised, the callback function is called with the
Error
object (if any) passed as the first argument. If no error was raised,
the first argument will be passed as null
.
const fs = require('fs');
function errorFirstCallback(err, data) {
if (err) {
console.error('There was an error', err);
return;
}
console.log(data);
}
fs.readFile('/some/file/that/does-not-exist', errorFirstCallback);
fs.readFile('/some/file/that/does-exist', errorFirstCallback);
The JavaScript try…catch
mechanism cannot be used to intercept errors
generated by asynchronous APIs. A common mistake for beginners is to try to
use throw
inside an error-first callback:
// THIS WILL NOT WORK:
const fs = require('fs');
try {
fs.readFile('/some/file/that/does-not-exist', (err, data) => {
// mistaken assumption: throwing here...
if (err) {
throw err;
}
});
} catch (err) {
// This will not catch the throw!
console.error(err);
}
This will not work because the callback function passed to fs.readFile()
is
called asynchronously. By the time the callback has been called, the
surrounding code (including the try { } catch (err) { }
block will have
already exited. Throwing an error inside the callback can crash the Node.js
process in most cases. If domains are enabled, or a handler has been
registered with process.on('uncaughtException')
, such errors can be
intercepted.
Class: Error#
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.
For crypto only, Error
objects will include the OpenSSL error stack in a
separate property called opensslErrorStack
if it is available when the error
is thrown.
All errors generated by Node.js, including all System and JavaScript errors,
will either be instances of, or inherit from, the Error
class.
new Error(message)#
message
<string>
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 message.toString()
. 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.
Error.captureStackTrace(targetObject[, constructorOpt])#
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 an end user. For instance:
function MyError() {
Error.captureStackTrace(this, MyError);
}
// Without passing MyError to captureStackTrace, the MyError
// frame would show up in the .stack property. By passing
// the constructor, we omit that frame, and retain all frames below it.
new MyError().stack;
Error.stackTraceLimit#
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.
error.code#
The error.code
property is a string label that identifies the kind of error.
See Node.js Error Codes for details about specific codes.
error.message#
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
error.stack#
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, 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.
System-level errors are generated as augmented Error
instances, which are
detailed here.
Class: AssertionError#
A subclass of Error
that indicates the failure of an assertion. For details,
see Class: assert.AssertionError
.
Class: RangeError#
A subclass of Error
that 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('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.
Class: ReferenceError#
A subclass of Error
that 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 should always be considered a bug in the code
or its dependencies.
Class: SyntaxError#
A subclass of Error
that 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('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.
Class: TypeError#
A subclass of Error
that indicates that a provided argument is not an
allowable type. For example, passing a function to a parameter which expects a
string would be considered a TypeError
.
require('url').parse(() => { });
// throws TypeError, since it expected a string
Node.js will generate and throw TypeError
instances immediately as a form
of argument validation.
Exceptions vs. Errors#
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.
System Errors#
System errors are generated when exceptions occur within the Node.js runtime environment. Typically, these are operational errors that occur when an application violates an operating system constraint such as attempting to read a file that does not exist or when the user does not have sufficient permissions.
System errors are typically generated at the syscall level: an exhaustive list
of error codes and their meanings is available by running man 2 intro
or
man 3 errno
on most Unices; or online.
In Node.js, system errors are represented as augmented Error
objects with
added properties.
Class: SystemError#
error.info#
SystemError
instances may have an additional info
property whose
value is an object with additional details about the error conditions.
The following properties are provided:
code
<string> The string error codeerrno
<number> The system-provided error numbermessage
<string> A system-provided human readable description of the errorsyscall
<string> The name of the system call that triggered the errorpath
<Buffer> When reporting a file system error, thepath
will identify the file path.dest
<Buffer> When reporting a file system error, thedest
will identify the file path destination (if any).
error.code#
The error.code
property is a string representing the error code, which is
typically E
followed by a sequence of capital letters.
error.errno#
The error.errno
property is a number or a string.
The number is a negative value which corresponds to the error code defined
in libuv Error handling
. See uv-errno.h
header file
(deps/uv/include/uv-errno.h
in the Node.js source tree) for details. In case
of a string, it is the same as error.code
.
error.syscall#
The error.syscall
property is a string describing the syscall that failed.
error.path#
When present (e.g. in fs
or child_process
), the error.path
property is a
string containing a relevant invalid pathname.
error.address#
When present (e.g. in net
or dgram
), the error.address
property is a
string describing the address to which the connection failed.
error.port#
When present (e.g. in net
or dgram
), the error.port
property is a number
representing the connection's port that is not available.
Common System Errors#
This list is not exhaustive, but enumerates many of the common system errors encountered when writing a Node.js program. An exhaustive list may be found here.
-
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
. -
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.
Node.js Error Codes#
ERR_AMBIGUOUS_ARGUMENT##
A function argument is being used in a way that suggests that the function
signature may be misunderstood. This is thrown by the 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.
ERR_ARG_NOT_ITERABLE##
An iterable argument (i.e. a value that works with for...of
loops) was
required, but not provided to a Node.js API.
ERR_ASSERTION##
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 assert
module.
ERR_ASYNC_CALLBACK##
An attempt was made to register something that is not a function as an
AsyncHooks
callback.
ERR_ASYNC_TYPE##
The type of an asynchronous resource was invalid. Note that users are also able to define their own types if using the public embedder API.
ERR_BUFFER_OUT_OF_BOUNDS##
An operation outside the bounds of a Buffer
was attempted.
ERR_BUFFER_TOO_LARGE##
An attempt has been made to create a Buffer
larger than the maximum allowed
size.
ERR_CANNOT_TRANSFER_OBJECT##
The value passed to postMessage()
contained an object that is not supported
for transferring.
ERR_CANNOT_WATCH_SIGINT##
Node.js was unable to watch for the SIGINT
signal.
ERR_CHILD_CLOSED_BEFORE_REPLY##
A child process was closed before the parent received a reply.
ERR_CHILD_PROCESS_IPC_REQUIRED##
Used when a child process is being forked without specifying an IPC channel.
ERR_CHILD_PROCESS_STDIO_MAXBUFFER##
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.
ERR_CLOSED_MESSAGE_PORT##
There was an attempt to use a MessagePort
instance in a closed
state, usually after .close()
has been called.
ERR_CONSOLE_WRITABLE_STREAM##
Console
was instantiated without stdout
stream, or Console
has a
non-writable stdout
or stderr
stream.
ERR_CONSTRUCT_CALL_REQUIRED##
A constructor for a class was called without new
.
ERR_CPU_USAGE##
The native call from process.cpuUsage
could not be processed.
ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED##
A client certificate engine was requested that is not supported by the version of OpenSSL being used.
ERR_CRYPTO_ECDH_INVALID_FORMAT##
An invalid value for the format
argument was passed to the crypto.ECDH()
class getPublicKey()
method.
ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY##
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.
ERR_CRYPTO_ENGINE_UNKNOWN##
An invalid crypto engine identifier was passed to
require('crypto').setEngine()
.
ERR_CRYPTO_FIPS_FORCED##
The --force-fips
command-line argument was used but there was an attempt
to enable or disable FIPS mode in the crypto
module.
ERR_CRYPTO_FIPS_UNAVAILABLE##
An attempt was made to enable or disable FIPS mode, but FIPS mode was not available.
ERR_CRYPTO_HASH_DIGEST_NO_UTF16##
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.
ERR_CRYPTO_HASH_FINALIZED##
hash.digest()
was called multiple times. The hash.digest()
method must
be called no more than one time per instance of a Hash
object.
ERR_CRYPTO_HASH_UPDATE_FAILED##
hash.update()
failed for any reason. This should rarely, if ever, happen.
ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS##
The selected public or private key encoding is incompatible with other options.
ERR_CRYPTO_INVALID_DIGEST##
An invalid crypto digest algorithm was specified.
ERR_CRYPTO_INVALID_STATE##
A crypto method was used on an object that was in an invalid state. For
instance, calling cipher.getAuthTag()
before calling cipher.final()
.
ERR_CRYPTO_PBKDF2_ERROR##
The PBKDF2 algorithm failed for unspecified reasons. OpenSSL does not provide more details and therefore neither does Node.js.
ERR_CRYPTO_SCRYPT_INVALID_PARAMETER##
One or more crypto.scrypt()
or crypto.scryptSync()
parameters are
outside their legal range.
ERR_CRYPTO_SCRYPT_NOT_SUPPORTED##
Node.js was compiled without scrypt
support. Not possible with the official
release binaries but can happen with custom builds, including distro builds.
ERR_CRYPTO_SIGN_KEY_REQUIRED##
A signing key
was not provided to the sign.sign()
method.
ERR_CRYPTO_TIMING_SAFE_EQUAL_LENGTH##
crypto.timingSafeEqual()
was called with Buffer
, TypedArray
, or
DataView
arguments of different lengths.
ERR_DNS_SET_SERVERS_FAILED##
c-ares
failed to set the DNS server.
ERR_DOMAIN_CALLBACK_NOT_AVAILABLE##
The 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.
ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE##
process.setUncaughtExceptionCaptureCallback()
could not be called
because the 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
domain
module had been loaded.
ERR_ENCODING_INVALID_ENCODED_DATA##
Data provided to util.TextDecoder()
API was invalid according to the encoding
provided.
ERR_ENCODING_NOT_SUPPORTED##
Encoding provided to util.TextDecoder()
API was not one of the
WHATWG Supported Encodings.
ERR_FALSY_VALUE_REJECTION##
A Promise
that was callbackified via util.callbackify()
was rejected with a
falsy value.
ERR_FS_FILE_TOO_LARGE##
An attempt has been made to read a file whose size is larger than the maximum
allowed size for a Buffer
.
ERR_FS_INVALID_SYMLINK_TYPE##
An invalid symlink type was passed to the fs.symlink()
or
fs.symlinkSync()
methods.
ERR_HTTP_HEADERS_SENT##
An attempt was made to add more headers after the headers had already been sent.
ERR_HTTP_INVALID_HEADER_VALUE##
An invalid HTTP header value was specified.
ERR_HTTP_INVALID_STATUS_CODE##
Status code was outside the regular status code range (100-999).
ERR_HTTP_TRAILER_INVALID##
The Trailer
header was set even though the transfer encoding does not support
that.
ERR_HTTP2_ALTSVC_INVALID_ORIGIN##
HTTP/2 ALTSVC frames require a valid origin.
ERR_HTTP2_ALTSVC_LENGTH##
HTTP/2 ALTSVC frames are limited to a maximum of 16,382 payload bytes.
ERR_HTTP2_CONNECT_AUTHORITY##
For HTTP/2 requests using the CONNECT
method, the :authority
pseudo-header
is required.
ERR_HTTP2_CONNECT_PATH##
For HTTP/2 requests using the CONNECT
method, the :path
pseudo-header is
forbidden.
ERR_HTTP2_CONNECT_SCHEME##
For HTTP/2 requests using the CONNECT
method, the :scheme
pseudo-header is
forbidden.
ERR_HTTP2_ERROR##
A non-specific HTTP/2 error has occurred.
ERR_HTTP2_GOAWAY_SESSION##
New HTTP/2 Streams may not be opened after the Http2Session
has received a
GOAWAY
frame from the connected peer.
ERR_HTTP2_HEADERS_AFTER_RESPOND##
An additional headers was specified after an HTTP/2 response was initiated.
ERR_HTTP2_HEADERS_SENT##
An attempt was made to send multiple response headers.
ERR_HTTP2_HEADER_SINGLE_VALUE##
Multiple values were provided for an HTTP/2 header field that was required to have only a single value.
ERR_HTTP2_INFO_STATUS_NOT_ALLOWED##
Informational HTTP status codes (1xx
) may not be set as the response status
code on HTTP/2 responses.
ERR_HTTP2_INVALID_CONNECTION_HEADERS##
HTTP/1 connection specific headers are forbidden to be used in HTTP/2 requests and responses.
ERR_HTTP2_INVALID_HEADER_VALUE##
An invalid HTTP/2 header value was specified.
ERR_HTTP2_INVALID_INFO_STATUS##
An invalid HTTP informational status code has been specified. Informational
status codes must be an integer between 100
and 199
(inclusive).
ERR_HTTP2_INVALID_ORIGIN##
HTTP/2 ORIGIN
frames require a valid origin.
ERR_HTTP2_INVALID_PACKED_SETTINGS_LENGTH##
Input Buffer
and Uint8Array
instances passed to the
http2.getUnpackedSettings()
API must have a length that is a multiple of
six.
ERR_HTTP2_INVALID_PSEUDOHEADER##
Only valid HTTP/2 pseudoheaders (:status
, :path
, :authority
, :scheme
,
and :method
) may be used.
ERR_HTTP2_INVALID_SESSION##
An action was performed on an Http2Session
object that had already been
destroyed.
ERR_HTTP2_INVALID_SETTING_VALUE##
An invalid value has been specified for an HTTP/2 setting.
ERR_HTTP2_INVALID_STREAM##
An operation was performed on a stream that had already been destroyed.
ERR_HTTP2_MAX_PENDING_SETTINGS_ACK##
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.
ERR_HTTP2_NESTED_PUSH##
An attempt was made to initiate a new push stream from within a push stream. Nested push streams are not permitted.
ERR_HTTP2_NO_SOCKET_MANIPULATION##
An attempt was made to directly manipulate (read, write, pause, resume, etc.) a
socket attached to an Http2Session
.
ERR_HTTP2_ORIGIN_LENGTH##
HTTP/2 ORIGIN
frames are limited to a length of 16382 bytes.
ERR_HTTP2_OUT_OF_STREAMS##
The number of streams created on a single HTTP/2 session reached the maximum limit.
ERR_HTTP2_PAYLOAD_FORBIDDEN##
A message payload was specified for an HTTP response code for which a payload is forbidden.
ERR_HTTP2_PING_CANCEL##
An HTTP/2 ping was canceled.
ERR_HTTP2_PING_LENGTH##
HTTP/2 ping payloads must be exactly 8 bytes in length.
ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED##
An HTTP/2 pseudo-header has been used inappropriately. Pseudo-headers are header
key names that begin with the :
prefix.
ERR_HTTP2_PUSH_DISABLED##
An attempt was made to create a push stream, which had been disabled by the client.
ERR_HTTP2_SEND_FILE##
An attempt was made to use the Http2Stream.prototype.responseWithFile()
API to
send a directory.
ERR_HTTP2_SEND_FILE_NOSEEK##
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.
ERR_HTTP2_SESSION_ERROR##
The Http2Session
closed with a non-zero error code.
ERR_HTTP2_SETTINGS_CANCEL##
The Http2Session
settings canceled.
ERR_HTTP2_SOCKET_BOUND##
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.
ERR_HTTP2_SOCKET_UNBOUND##
An attempt was made to use the socket
property of an Http2Session
that
has already been closed.
ERR_HTTP2_STATUS_101##
Use of the 101
Informational status code is forbidden in HTTP/2.
ERR_HTTP2_STATUS_INVALID##
An invalid HTTP status code has been specified. Status codes must be an integer
between 100
and 599
(inclusive).
ERR_HTTP2_STREAM_CANCEL##
An Http2Stream
was destroyed before any data was transmitted to the connected
peer.
ERR_HTTP2_STREAM_ERROR##
A non-zero error code was been specified in an RST_STREAM
frame.
ERR_HTTP2_STREAM_SELF_DEPENDENCY##
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.
ERR_HTTP2_TRAILERS_ALREADY_SENT##
Trailing headers have already been sent on the Http2Stream
.
ERR_HTTP2_TRAILERS_NOT_READY##
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
.
ERR_HTTP2_UNSUPPORTED_PROTOCOL##
http2.connect()
was passed a URL that uses any protocol other than http:
or
https:
.
ERR_INDEX_OUT_OF_RANGE##
A given index was out of the accepted range (e.g. negative offsets).
ERR_INSPECTOR_ALREADY_CONNECTED##
While using the inspector
module, an attempt was made to connect when the
inspector was already connected.
ERR_INSPECTOR_CLOSED##
While using the inspector
module, an attempt was made to use the inspector
after the session had already closed.
ERR_INSPECTOR_NOT_AVAILABLE##
The inspector
module is not available for use.
ERR_INSPECTOR_NOT_CONNECTED##
While using the inspector
module, an attempt was made to use the inspector
before it was connected.
ERR_INVALID_ADDRESS_FAMILY##
The provided address family is not understood by the Node.js API.
ERR_INVALID_ARG_TYPE##
An argument of the wrong type was passed to a Node.js API.
ERR_INVALID_ARG_VALUE##
An invalid or unsupported value was passed for a given argument.
ERR_INVALID_ARRAY_LENGTH##
An array was not of the expected length or in a valid range.
ERR_INVALID_ASYNC_ID##
An invalid asyncId
or triggerAsyncId
was passed using AsyncHooks
. An id
less than -1 should never happen.
ERR_INVALID_BUFFER_SIZE##
A swap was performed on a Buffer
but its size was not compatible with the
operation.
ERR_INVALID_CALLBACK##
A callback function was required but was not been provided to a Node.js API.
ERR_INVALID_CHAR##
Invalid characters were detected in headers.
ERR_INVALID_CURSOR_POS##
A cursor on a given stream cannot be moved to a specified row without a specified column.
ERR_INVALID_DOMAIN_NAME##
hostname
can not be parsed from a provided URL.
ERR_INVALID_FD##
A file descriptor ('fd') was not valid (e.g. it was a negative value).
ERR_INVALID_FD_TYPE##
A file descriptor ('fd') type was not valid.
ERR_INVALID_FILE_URL_HOST##
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.
ERR_INVALID_FILE_URL_PATH##
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.
ERR_INVALID_HANDLE_TYPE##
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.
ERR_INVALID_HTTP_TOKEN##
An invalid HTTP token was supplied.
ERR_INVALID_IP_ADDRESS##
An IP address is not valid.
ERR_INVALID_OPT_VALUE##
An invalid or unexpected value was passed in an options object.
ERR_INVALID_OPT_VALUE_ENCODING##
An invalid or unknown file encoding was passed.
ERR_INVALID_PERFORMANCE_MARK##
While using the Performance Timing API (perf_hooks
), a performance mark is
invalid.
ERR_INVALID_PROTOCOL##
An invalid options.protocol
was passed.
ERR_INVALID_REPL_EVAL_CONFIG##
Both breakEvalOnSigint
and eval
options were set in the REPL config, which
is not supported.
ERR_INVALID_RETURN_PROPERTY##
Thrown in case a function option does not provide a valid value for one of its returned object properties on execution.
ERR_INVALID_RETURN_PROPERTY_VALUE##
Thrown in case a function option does not provide an expected value type for one of its returned object properties on execution.
ERR_INVALID_RETURN_VALUE##
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.
ERR_INVALID_SYNC_FORK_INPUT##
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.
ERR_INVALID_THIS##
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'
ERR_INVALID_TRANSFER_OBJECT##
An invalid transfer object was passed to postMessage()
.
ERR_INVALID_TUPLE##
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.
ERR_INVALID_URI##
An invalid URI was passed.
ERR_INVALID_URL##
An invalid URL was passed to the WHATWG
URL
constructor to be parsed. The thrown error object
typically has an additional property 'input'
that contains the URL that failed
to parse.
ERR_INVALID_URL_SCHEME##
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.
ERR_IPC_CHANNEL_CLOSED##
An attempt was made to use an IPC communication channel that was already closed.
ERR_IPC_DISCONNECTED##
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.
ERR_IPC_ONE_PIPE##
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.
ERR_IPC_SYNC_FORK##
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.
ERR_MEMORY_ALLOCATION_FAILED##
An attempt was made to allocate memory (usually in the C++ layer) but it failed.
ERR_METHOD_NOT_IMPLEMENTED##
A method is required but not implemented.
ERR_MISSING_ARGS##
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.
ERR_MISSING_DYNAMIC_INSTANTIATE_HOOK##
An ES6 module loader hook specified format: 'dynamic'
but did not provide
a dynamicInstantiate
hook.
ERR_MISSING_MESSAGE_PORT_IN_TRANSFER_LIST##
A MessagePort
was found in the object passed to a postMessage()
call,
but not provided in the transferList
for that call.
ERR_MISSING_MODULE##
An ES6 module could not be resolved.
ERR_MISSING_PLATFORM_FOR_WORKER##
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.
ERR_MODULE_RESOLUTION_LEGACY##
A failure occurred resolving imports in an ES6 module.
ERR_MULTIPLE_CALLBACK##
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.
ERR_NAPI_CONS_FUNCTION##
While using N-API
, a constructor passed was not a function.
ERR_NAPI_INVALID_DATAVIEW_ARGS##
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
.
ERR_NAPI_INVALID_TYPEDARRAY_ALIGNMENT##
While calling napi_create_typedarray()
, the provided offset
was not a
multiple of the element size.
ERR_NAPI_INVALID_TYPEDARRAY_LENGTH##
While calling napi_create_typedarray()
, (length * size_of_element) + byte_offset
was larger than the length of given buffer
.
ERR_NAPI_TSFN_CALL_JS##
An error occurred while invoking the JavaScript portion of the thread-safe function.
ERR_NAPI_TSFN_GET_UNDEFINED##
An error occurred while attempting to retrieve the JavaScript undefined
value.
ERR_NAPI_TSFN_START_IDLE_LOOP##
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.
ERR_NAPI_TSFN_STOP_IDLE_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.
ERR_NO_CRYPTO##
An attempt was made to use crypto features while Node.js was not compiled with OpenSSL crypto support.
ERR_NO_ICU##
An attempt was made to use features that require ICU, but Node.js was not compiled with ICU support.
ERR_NO_LONGER_SUPPORTED##
A Node.js API was called in an unsupported manner, such as
Buffer.write(string, encoding, offset[, length])
.
ERR_OUT_OF_RANGE##
A given value is out of the accepted range.
ERR_REQUIRE_ESM##
An attempt was made to require()
an ES6 module.
ERR_SCRIPT_EXECUTION_INTERRUPTED##
Script execution was interrupted by SIGINT
(For example, when Ctrl+C was
pressed).
ERR_SERVER_ALREADY_LISTEN##
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.
ERR_SERVER_NOT_RUNNING##
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.
ERR_SOCKET_ALREADY_BOUND##
An attempt was made to bind a socket that has already been bound.
ERR_SOCKET_BAD_BUFFER_SIZE##
An invalid (negative) size was passed for either the recvBufferSize
or
sendBufferSize
options in dgram.createSocket()
.
ERR_SOCKET_BAD_PORT##
An API function expecting a port >= 0 and < 65536 received an invalid value.
ERR_SOCKET_BAD_TYPE##
An API function expecting a socket type (udp4
or udp6
) received an invalid
value.
ERR_SOCKET_BUFFER_SIZE##
While using dgram.createSocket()
, the size of the receive or send Buffer
could not be determined.
ERR_SOCKET_CANNOT_SEND##
Data could be sent on a socket.
ERR_SOCKET_CLOSED##
An attempt was made to operate on an already closed socket.
ERR_SOCKET_DGRAM_NOT_RUNNING##
A call was made and the UDP subsystem was not running.
ERR_STREAM_CANNOT_PIPE##
An attempt was made to call stream.pipe()
on a Writable
stream.
ERR_STREAM_DESTROYED##
A stream method was called that cannot complete because the stream was
destroyed using stream.destroy()
.
ERR_STREAM_NULL_VALUES##
An attempt was made to call stream.write()
with a null
chunk.
ERR_STREAM_PREMATURE_CLOSE##
An error returned by stream.finished()
and stream.pipeline()
, when a stream
or a pipeline ends non gracefully with no explicit error.
ERR_STREAM_PUSH_AFTER_EOF##
An attempt was made to call stream.push()
after a null
(EOF) had been
pushed to the stream.
ERR_STREAM_UNSHIFT_AFTER_END_EVENT##
An attempt was made to call stream.unshift()
after the 'end'
event was
emitted.
ERR_STREAM_WRAP##
Prevents an abort if a string decoder was set on the Socket or if the decoder
is in objectMode
.
const Socket = require('net').Socket;
const instance = new Socket();
instance.setEncoding('utf8');
ERR_STREAM_WRITE_AFTER_END##
An attempt was made to call stream.write()
after stream.end()
has been
called.
ERR_STRING_TOO_LONG##
An attempt has been made to create a string longer than the maximum allowed length.
ERR_SYSTEM_ERROR##
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.
ERR_TLS_CERT_ALTNAME_INVALID##
While using TLS, the hostname/IP of the peer did not match any of the
subjectAltNames
in its certificate.
ERR_TLS_DH_PARAM_SIZE##
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.
ERR_TLS_HANDSHAKE_TIMEOUT##
A TLS/SSL handshake timed out. In this case, the server must also abort the connection.
ERR_TLS_RENEGOTIATE##
An attempt to renegotiate the TLS session failed.
ERR_TLS_RENEGOTIATION_DISABLED##
An attempt was made to renegotiate TLS on a socket instance with TLS disabled.
ERR_TLS_REQUIRED_SERVER_NAME##
While using TLS, the server.addContext()
method was called without providing
a hostname in the first parameter.
ERR_TLS_SESSION_ATTACK##
An excessive amount of TLS renegotiations is detected, which is a potential vector for denial-of-service attacks.
ERR_TLS_SNI_FROM_SERVER##
An attempt was made to issue Server Name Indication from a TLS server-side socket, which is only valid from a client.
ERR_TRACE_EVENTS_CATEGORY_REQUIRED##
The trace_events.createTracing()
method requires at least one trace event
category.
ERR_TRACE_EVENTS_UNAVAILABLE##
The trace_events
module could not be loaded because Node.js was compiled with
the --without-v8-platform
flag.
ERR_TRANSFERRING_EXTERNALIZED_SHAREDARRAYBUFFER##
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.
ERR_TRANSFORM_ALREADY_TRANSFORMING##
A Transform
stream finished while it was still transforming.
ERR_TRANSFORM_WITH_LENGTH_0##
A Transform
stream finished with data still in the write buffer.
ERR_TTY_INIT_FAILED##
The initialization of a TTY failed due to a system error.
ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET##
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.
ERR_UNESCAPED_CHARACTERS##
A string that contained unescaped characters was received.
ERR_UNHANDLED_ERROR##
An unhandled error occurred (for instance, when an 'error'
event is emitted
by an EventEmitter
but an 'error'
handler is not registered).
ERR_UNKNOWN_BUILTIN_MODULE##
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.
ERR_UNKNOWN_ENCODING##
An invalid or unknown encoding option was passed to an API.
ERR_UNKNOWN_FILE_EXTENSION##
An attempt was made to load a module with an unknown or unsupported file extension.
ERR_UNKNOWN_MODULE_FORMAT##
An attempt was made to load a module with an unknown or unsupported format.
ERR_UNKNOWN_SIGNAL##
An invalid or unknown process signal was passed to an API expecting a valid
signal (such as subprocess.kill()
).
ERR_UNKNOWN_STDIN_TYPE##
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.
ERR_UNKNOWN_STREAM_TYPE##
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.
ERR_V8BREAKITERATOR##
The V8 BreakIterator
API was used but the full ICU data set is not installed.
ERR_VALID_PERFORMANCE_ENTRY_TYPE##
While using the Performance Timing API (perf_hooks
), no valid performance
entry types were found.
ERR_VM_MODULE_ALREADY_LINKED##
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'
)
ERR_VM_MODULE_DIFFERENT_CONTEXT##
The module being returned from the linker function is from a different context than the parent module. Linked modules must share the same context.
ERR_VM_MODULE_LINKING_ERRORED##
The linker function returned a module for which linking has failed.
ERR_VM_MODULE_NOT_LINKED##
The module must be successfully linked before instantiation.
ERR_VM_MODULE_NOT_MODULE##
The fulfilled value of a linking promise is not a vm.SourceTextModule
object.
ERR_VM_MODULE_STATUS##
The current module's status does not allow for this operation. The specific meaning of the error depends on the specific function.
ERR_WORKER_PATH##
The path for the main script of a worker is neither an absolute path
nor a relative path starting with ./
or ../
.
ERR_WORKER_UNSERIALIZABLE_ERROR##
All attempts at serializing an uncaught exception from a worker thread failed.
ERR_WORKER_UNSUPPORTED_EXTENSION##
The pathname used for the main script of a worker has an unknown file extension.
ERR_ZLIB_INITIALIZATION_FAILED##
Creation of a zlib
object failed due to incorrect configuration.
MODULE_NOT_FOUND#
A module file could not be resolved while attempting a require()
or
import
operation.
Legacy Node.js Error Codes#
ERR_HTTP2_FRAME_ERROR##
Used when a failure occurs sending an individual frame on the HTTP/2 session.
ERR_HTTP2_HEADERS_OBJECT##
Used when an HTTP/2 Headers Object is expected.
ERR_HTTP2_HEADER_REQUIRED##
Used when a required header is missing in an HTTP/2 message.
ERR_HTTP2_INFO_HEADERS_AFTER_RESPOND##
HTTP/2 informational headers must only be sent prior to calling the
Http2Stream.prototype.respond()
method.
ERR_HTTP2_STREAM_CLOSED##
Used when an action has been performed on an HTTP/2 Stream that has already been closed.
ERR_HTTP_INVALID_CHAR##
Used when an invalid character is found in an HTTP response status message (reason phrase).
ERR_NAPI_CONS_PROTOTYPE_OBJECT##
Used by the N-API
when Constructor.prototype
is not an object.
ERR_OUTOFMEMORY##
Used generically to identify that an operation caused an out of memory condition.
ERR_PARSE_HISTORY_DATA##
The repl
module was unable to parse data from the REPL history file.
ERR_STDERR_CLOSE##
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.
ERR_STDOUT_CLOSE##
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.
ERR_STREAM_READ_NOT_IMPLEMENTED##
Used when an attempt is made to use a readable stream that has not implemented
readable._read()
.
ERR_TLS_RENEGOTIATION_FAILED##
Used when a TLS renegotiation request has failed in a non-specific way.
ERR_UNKNOWN_BUILTIN_MODULE##
The 'ERR_UNKNOWN_BUILTIN_MODULE'
error code is 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.
ERR_VALUE_OUT_OF_RANGE##
Used when a given value is out of the accepted range.
ERR_ZLIB_BINDING_CLOSED##
Used when an attempt is made to use a zlib
object after it has already been
closed.
Other error codes#
These errors have never been released, but had been present on master between releases.
ERR_FS_WATCHER_ALREADY_STARTED##
An attempt was made to start a watcher returned by fs.watch()
that has
already been started.
ERR_FS_WATCHER_NOT_STARTED##
An attempt was made to initiate operations on a watcher returned by
fs.watch()
that has not yet been started.
ERR_HTTP2_ALREADY_SHUTDOWN##
Occurs with multiple attempts to shutdown an HTTP/2 session.
ERR_HTTP2_ERROR##
A non-specific HTTP/2 error has occurred.
ERR_INVALID_REPL_HISTORY##
Used in the repl
in case the old history file is used and an error occurred
while trying to read and parse it.
ERR_MISSING_DYNAMIC_INSTANTIATE_HOOK##
Used when an ES6 module loader hook specifies format: 'dynamic'
but does
not provide a dynamicInstantiate
hook.
ERR_STREAM_HAS_STRINGDECODER##
Used to prevent an abort if a string decoder was set on the Socket.
const Socket = require('net').Socket;
const instance = new Socket();
instance.setEncoding('utf8');
ERR_STRING_TOO_LARGE##
An attempt has been made to create a string larger than the maximum allowed size.