# 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 the `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.

## 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][try-catch] provided by the
JavaScript language.

```js
// 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 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 an
  `Error` object passed as the first argument to that function. If that first
  argument is not `null` and is an instance of `Error`, then an error occurred
  that should be handled.


  ```js
  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.

  ```js
  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 using
  `try…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`][domains] module is
used appropriately or a handler has been registered for the
[`'uncaughtException'`][] event.

```js
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`.

```js
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:

```js
// 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.

```js
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:

```js
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

* {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.

### error.code

* {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.

### error.message

* {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).

```js
const err = new Error('The message');
console.error(err.message);
// Prints: The message
```

### error.stack

* {string}

The `error.stack` property is a string describing the point in the code at which
the `Error` was instantiated.

```txt
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:

```js
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](#errors_system_errors).

## 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.

```js
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.

```js
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.

```js
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`.

```js
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

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.

System errors are usually generated at the syscall level. For a comprehensive
list, see the [`errno`(3) man page][].

In Node.js, system errors are `Error` objects with extra properties.

### Class: SystemError

* `address` {string} If present, the address to which a network connection
  failed
* `code` {string} The string error code
* `dest` {string} If present, the file path destination when reporting a file
  system error
* `errno` {number|string} The system-provided error number
* `info` {Object} If present, extra details about the error condition
* `message` {string} A system-provided human-readable description of the error
* `path` {string} If present, the file path when reporting a file system error
* `port` {number} If present, the network connection port that is not available
* `syscall` {string} The name of the system call that triggered the error

#### error.address

* {string}

If present, `error.address` is a string describing the address to which a
network connection failed.

#### error.code

* {string}

The `error.code` property is a string representing the error code.

#### error.dest

* {string}

If present, `error.dest` is the file path destination when reporting a file
system error.

#### error.errno

* {string|number}

The `error.errno` property is a number or a string. If it is a number, it is a
negative value which corresponds to the error code defined in
[`libuv Error handling`]. See the libuv `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.info

* {Object}

If present, `error.info` is an object with details about the error condition.

#### error.message

* {string}

`error.message` is a system-provided human-readable description of the error.

#### error.path

* {string}

If present, `error.path` is a string containing a relevant invalid pathname.

#### error.port

* {number}

If present, `error.port` is the network connection port that is not available.

#### error.syscall

* {string}

The `error.syscall` property is a string describing the [syscall][] that failed.

### Common System Errors

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`][], or [`https`][]) 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 the [`http`][]
  and [`net`][] 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, run
  `ulimit -n 2048` in the same shell that will run the Node.js process.

- `ENOENT` (No such file or directory): Commonly raised by [`fs`][] 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 by [`fs.readdir`][].

- `ENOTEMPTY` (Directory not empty): A directory with entries was the target
  of an operation that requires an empty directory — usually [`fs.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 the [`net`][] and
  [`http`][] 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 by [`http`][] or [`net`][] — often a sign that a `socket.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_BROTLI_COMPRESSION_FAILED

Data passed to a Brotli stream was not successfully compressed.

### ERR_BROTLI_INVALID_PARAM

An invalid parameter key was passed during construction of a Brotli stream.

### 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.

```js
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][WHATWG URL API]
[`URLSearchParams` constructor][`new URLSearchParams(iterable)`] 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][WHATWG URL API]
[`URL` constructor][`new URL(input)`] 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

> Stability: 1 - Experimental

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

> Stability: 1 - Experimental

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

> Stability: 1 - Experimental

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

> Stability: 1 - Experimental

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`.

```js
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_INVALID_PROTOCOL_VERSION

Valid TLS protocol versions are `'TLSv1'`, `'TLSv1.1'`, or `'TLSv1.2'`.

### ERR_TLS_PROTOCOL_VERSION_CONFLICT

Attempting to set a TLS protocol `minVersion` or `maxVersion` conflicts with an
attempt to set the `secureProtocol` explicitly. Use one mechanism or the other.

### 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

> Stability: 1 - Experimental

An attempt was made to load a module with an unknown or unsupported file
extension.

### ERR_UNKNOWN_MODULE_FORMAT

> Stability: 1 - Experimental

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_DYNAMIC_IMPORT_CALLBACK_MISSING

A dynamic import callback was not specified.

### 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.

### HPE_HEADER_OVERFLOW

Too much HTTP header data was received. In order to protect against malicious or
malconfigured clients, if more than 8KB 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.

### MODULE_NOT_FOUND

A module file could not be resolved while attempting a [`require()`][] or
`import` operation.

## Legacy Node.js Error Codes

> Stability: 0 - Deprecated. These error codes are either inconsistent, or have
> been removed.

### 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.

```js
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.

[`'uncaughtException'`]: process.html#process_event_uncaughtexception
[`--force-fips`]: cli.html#cli_force_fips
[`Class: assert.AssertionError`]: assert.html#assert_class_assert_assertionerror
[`ERR_INVALID_ARG_TYPE`]: #ERR_INVALID_ARG_TYPE
[`EventEmitter`]: events.html#events_class_eventemitter
[`Writable`]: stream.html#stream_class_stream_writable
[`child_process`]: child_process.html
[`cipher.getAuthTag()`]: crypto.html#crypto_cipher_getauthtag
[`crypto.scrypt()`]: crypto.html#crypto_crypto_scrypt_password_salt_keylen_options_callback
[`crypto.scryptSync()`]: crypto.html#crypto_crypto_scryptsync_password_salt_keylen_options
[`crypto.timingSafeEqual()`]: crypto.html#crypto_crypto_timingsafeequal_a_b
[`dgram.createSocket()`]: dgram.html#dgram_dgram_createsocket_options_callback
[`errno`(3) man page]: http://man7.org/linux/man-pages/man3/errno.3.html
[`fs.readFileSync`]: fs.html#fs_fs_readfilesync_path_options
[`fs.readdir`]: fs.html#fs_fs_readdir_path_options_callback
[`fs.symlink()`]: fs.html#fs_fs_symlink_target_path_type_callback
[`fs.symlinkSync()`]: fs.html#fs_fs_symlinksync_target_path_type
[`fs.unlink`]: fs.html#fs_fs_unlink_path_callback
[`fs`]: fs.html
[`hash.digest()`]: crypto.html#crypto_hash_digest_encoding
[`hash.update()`]: crypto.html#crypto_hash_update_data_inputencoding
[`http`]: http.html
[`https`]: https.html
[`libuv Error handling`]: http://docs.libuv.org/en/v1.x/errors.html
[`net`]: net.html
[`new URL(input)`]: url.html#url_constructor_new_url_input_base
[`new URLSearchParams(iterable)`]: url.html#url_constructor_new_urlsearchparams_iterable
[`process.send()`]: process.html#process_process_send_message_sendhandle_options_callback
[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_fn
[`readable._read()`]: stream.html#stream_readable_read_size_1
[`require('crypto').setEngine()`]: crypto.html#crypto_crypto_setengine_engine_flags
[`require()`]: modules.html#modules_require
[`server.close()`]: net.html#net_server_close_callback
[`server.listen()`]: net.html#net_server_listen
[`sign.sign()`]: crypto.html#crypto_sign_sign_privatekey_outputencoding
[`stream.pipe()`]: stream.html#stream_readable_pipe_destination_options
[`stream.push()`]: stream.html#stream_readable_push_chunk_encoding
[`stream.unshift()`]: stream.html#stream_readable_unshift_chunk
[`stream.write()`]: stream.html#stream_writable_write_chunk_encoding_callback
[`subprocess.kill()`]: child_process.html#child_process_subprocess_kill_signal
[`subprocess.send()`]: child_process.html#child_process_subprocess_send_message_sendhandle_options_callback
[`zlib`]: zlib.html
[ES6 module]: esm.html
[ICU]: intl.html#intl_internationalization_support
[Node.js Error Codes]: #nodejs-error-codes
[V8's stack trace API]: https://github.com/v8/v8/wiki/Stack-Trace-API
[WHATWG Supported Encodings]: util.html#util_whatwg_supported_encodings
[WHATWG URL API]: url.html#url_the_whatwg_url_api
[crypto digest algorithm]: crypto.html#crypto_crypto_gethashes
[domains]: domain.html
[event emitter-based]: events.html#events_class_eventemitter
[file descriptors]: https://en.wikipedia.org/wiki/File_descriptor
[stream-based]: stream.html
[syscall]: http://man7.org/linux/man-pages/man2/syscalls.2.html
[try-catch]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch
[vm]: vm.html
