A generic JavaScript Error object that does not denote any specific\ncircumstance of why the error occurred. Error objects capture a "stack trace"\ndetailing the point in the code at which the Error was instantiated, and may\nprovide a text description of the error.
All errors generated by Node.js, including all System and JavaScript errors,\nwill either be instances of, or inherit from, the Error class.
Creates a .stack property on targetObject, which when accessed returns\na string representing the location in the code at which\nError.captureStackTrace() was called.
const myObject = {};\nError.captureStackTrace(myObject);\nmyObject.stack; // similar to `new Error().stack`\nThe first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.
The optional constructorOpt argument accepts a function. If given, all frames\nabove constructorOpt, including constructorOpt, will be omitted from the\ngenerated stack trace.
The constructorOpt argument is useful for hiding implementation\ndetails of error generation from an end user. For instance:
function MyError() {\n Error.captureStackTrace(this, MyError);\n}\n\n// Without passing MyError to captureStackTrace, the MyError\n// frame would show up in the .stack property. By passing\n// the constructor, we omit that frame, and retain all frames below it.\nnew MyError().stack;\nThe Error.stackTraceLimit property specifies the number of stack frames\ncollected by a stack trace (whether generated by new Error().stack or\nError.captureStackTrace(obj)).
The default value is 10 but may be set to any valid JavaScript number. Changes\nwill 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\nnot capture any frames.
\n" }, { "textRaw": "`code` {string} ", "type": "string", "name": "code", "desc": "The error.code property is a string label that identifies the kind of error.\nSee Node.js Error Codes for details about specific codes.
The error.message property is the string description of the error as set by\ncalling new Error(message). The message passed to the constructor will also\nappear in the first line of the stack trace of the Error, however changing\nthis property after the Error object is created may not change the first\nline of the stack trace (for example, when error.stack is read before this\nproperty is changed).
const err = new Error('The message');\nconsole.error(err.message);\n// Prints: The message\nThe error.stack property is a string describing the point in the code at which\nthe Error was instantiated.
For example:
\nError: Things keep happening!\n at /home/gbusey/file.js:525:2\n at Frobnicator.refrobulate (/home/gbusey/business-logic.js:424:21)\n at Actor.<anonymous> (/home/gbusey/actors.js:400:8)\n at increaseSynergy (/home/gbusey/actors.js:701:6)\nThe first line is formatted as <error class name>: <error message>, and\nis followed by a series of stack frames (each line beginning with "at ").\nEach frame describes a call site within the code that lead to the error being\ngenerated. V8 attempts to display a name for each function (by variable name,\nfunction name, or object method name), but occasionally it will not be able to\nfind a suitable name. If V8 cannot determine a name for the function, only\nlocation information will be displayed for that frame. Otherwise, the\ndetermined function name will be displayed with location information appended\nin parentheses.
It is important to note that frames are only generated for JavaScript\nfunctions. If, for example, execution synchronously passes through a C++ addon\nfunction called cheetahify, which itself calls a JavaScript function, the\nframe representing the cheetahify call will not be present in the stack\ntraces:
const cheetahify = require('./native-binding.node');\n\nfunction makeFaster() {\n // cheetahify *synchronously* calls speedy.\n cheetahify(function speedy() {\n throw new Error('oh no!');\n });\n}\n\nmakeFaster();\n// will throw:\n// /home/gbusey/file.js:6\n// throw new Error('oh no!');\n// ^\n// Error: oh no!\n// at speedy (/home/gbusey/file.js:6:11)\n// at makeFaster (/home/gbusey/file.js:5:3)\n// at Object.<anonymous> (/home/gbusey/file.js:10:1)\n// at Module._compile (module.js:456:26)\n// at Object.Module._extensions..js (module.js:474:10)\n// at Module.load (module.js:356:32)\n// at Function.Module._load (module.js:312:12)\n// at Function.Module.runMain (module.js:497:10)\n// at startup (node.js:119:16)\n// at node.js:906:3\nThe location information will be one of:
\nnative, if the frame represents a call internal to V8 (as in [].forEach).plain-filename.js:line:column, if the frame represents a call internal\n to Node.js./absolute/path/to/file.js:line:column, if the frame represents a call in\na user program, or its dependencies.The string representing the stack trace is lazily generated when the\nerror.stack property is accessed.
The number of frames captured by the stack trace is bounded by the smaller of\nError.stackTraceLimit or the number of available frames on the current event\nloop tick.
System-level errors are generated as augmented Error instances, which are\ndetailed here.
Creates a new Error object and sets the error.message property to the\nprovided text message. If an object is passed as message, the text message\nis generated by calling message.toString(). The error.stack property will\nrepresent the point in the code at which new Error() was called. Stack traces\nare dependent on V8's stack trace API. Stack traces extend only to either\n(a) the beginning of synchronous code execution, or (b) the number of frames\ngiven by the property Error.stackTraceLimit, whichever is smaller.
Creates a new Error object and sets the error.message property to the\nprovided text message. If an object is passed as message, the text message\nis generated by calling message.toString(). The error.stack property will\nrepresent the point in the code at which new Error() was called. Stack traces\nare dependent on V8's stack trace API. Stack traces extend only to either\n(a) the beginning of synchronous code execution, or (b) the number of frames\ngiven by the property Error.stackTraceLimit, whichever is smaller.
A subclass of Error that indicates the failure of an assertion. Such errors\ncommonly indicate inequality of actual and expected value.
For example:
\nassert.strictEqual(1, 2);\n// AssertionError [ERR_ASSERTION]: 1 === 2\nA subclass of Error that indicates that a provided argument was not within the\nset or range of acceptable values for a function; whether that is a numeric\nrange, or outside the set of options for a given function parameter.
For example:
\nrequire('net').connect(-1);\n// throws "RangeError: "port" option should be >= 0 and < 65536: -1"\nNode.js will generate and throw RangeError instances immediately as a form\nof argument validation.
A subclass of Error that indicates that an attempt is being made to access a\nvariable that is not defined. Such errors commonly indicate typos in code, or\nan otherwise broken program.
While client code may generate and propagate these errors, in practice, only V8\nwill do so.
\ndoesNotExist;\n// throws ReferenceError, doesNotExist is not a variable in this program.\nUnless an application is dynamically generating and running code,\nReferenceError instances should always be considered a bug in the code\nor its dependencies.
A subclass of Error that indicates that a program is not valid JavaScript.\nThese errors may only be generated and propagated as a result of code\nevaluation. Code evaluation may happen as a result of eval, Function,\nrequire, or vm. These errors are almost always indicative of a broken\nprogram.
try {\n require('vm').runInThisContext('binary ! isNotOk');\n} catch (err) {\n // err will be a SyntaxError\n}\nSyntaxError instances are unrecoverable in the context that created them –\nthey may only be caught by other contexts.
A subclass of Error that indicates that a provided argument is not an\nallowable type. For example, passing a function to a parameter which expects a\nstring would be considered a TypeError.
require('url').parse(() => { });\n// throws TypeError, since it expected a string\nNode.js will generate and throw TypeError instances immediately as a form\nof argument validation.
Applications running in Node.js will generally experience four categories of\nerrors:
\neval() fails.assert module.All JavaScript and System errors raised by Node.js inherit from, or are\ninstances of, the standard JavaScript {Error} class and are guaranteed\nto provide at least the properties available on that class.
\n", "miscs": [ { "textRaw": "Error Propagation and Interception", "name": "Error Propagation and Interception", "type": "misc", "desc": "Node.js supports several mechanisms for propagating and handling errors that\noccur while an application is running. How these errors are reported and\nhandled depends entirely on the type of Error and the style of the API that is\ncalled.
\nAll JavaScript errors are handled as exceptions that immediately generate\nand throw an error using the standard JavaScript throw mechanism. These\nare handled using the try / catch construct provided by the\nJavaScript language.
// Throws with a ReferenceError because z is undefined\ntry {\n const m = 1;\n const n = m + z;\n} catch (err) {\n // Handle the error here.\n}\nAny use of the JavaScript throw mechanism will raise an exception that\nmust be handled using try / catch or the Node.js process will exit\nimmediately.
With few exceptions, Synchronous APIs (any blocking method that does not\naccept a callback function, such as fs.readFileSync), will use throw\nto report errors.
Errors that occur within Asynchronous APIs may be reported in multiple ways:
\ncallback function will accept an\nError object passed as the first argument to that function. If that first\nargument is not null and is an instance of Error, then an error occurred\nthat should be handled. const fs = require('fs');\n fs.readFile('a file that does not exist', (err, data) => {\n if (err) {\n console.error('There was an error reading the file!', err);\n return;\n }\n // Otherwise handle the data\n });\nWhen an asynchronous method is called on an object that is an EventEmitter,\nerrors can be routed to that object's 'error' event.
const net = require('net');\nconst connection = net.connect('localhost');\n\n// Adding an 'error' event handler to a stream:\nconnection.on('error', (err) => {\n // If the connection is reset by the server, or if it can't\n // connect at all, or on any sort of error encountered by\n // the connection, the error will be sent here.\n console.error(err);\n});\n\nconnection.pipe(process.stdout);\nA handful of typically asynchronous methods in the Node.js API may still\nuse the throw mechanism to raise exceptions that must be handled using\ntry / catch. There is no comprehensive list of such methods; please\nrefer to the documentation of each method to determine the appropriate\nerror handling mechanism required.
The use of the 'error' event mechanism is most common for stream-based\nand event emitter-based APIs, which themselves represent a series of\nasynchronous operations over time (as opposed to a single operation that may\npass or fail).
For all EventEmitter objects, if an 'error' event handler is not\nprovided, the error will be thrown, causing the Node.js process to report an\nunhandled exception and crash unless either: The domain module is\nused appropriately or a handler has been registered for the\nprocess.on('uncaughtException') event.
const EventEmitter = require('events');\nconst ee = new EventEmitter();\n\nsetImmediate(() => {\n // This will crash the process because no 'error' event\n // handler has been added.\n ee.emit('error', new Error('This will crash'));\n});\nErrors generated in this way cannot be intercepted using try / catch as\nthey are thrown after the calling code has already exited.
Developers must refer to the documentation for each method to determine\nexactly how errors raised by those methods are propagated.
\n", "miscs": [ { "textRaw": "Node.js style callbacks", "name": "Node.js style callbacks", "type": "misc", "desc": "Most asynchronous methods exposed by the Node.js core API follow an idiomatic\npattern referred to as a "Node.js style callback". With this pattern, a\ncallback function is passed to the method as an argument. When the operation\neither completes or an error is raised, the callback function is called with\nthe Error object (if any) passed as the first argument. If no error was raised,\nthe first argument will be passed as null.
const fs = require('fs');\n\nfunction nodeStyleCallback(err, data) {\n if (err) {\n console.error('There was an error', err);\n return;\n }\n console.log(data);\n}\n\nfs.readFile('/some/file/that/does-not-exist', nodeStyleCallback);\nfs.readFile('/some/file/that/does-exist', nodeStyleCallback);\nThe JavaScript try / catch mechanism cannot be used to intercept errors\ngenerated by asynchronous APIs. A common mistake for beginners is to try to\nuse throw inside a Node.js style callback:
// THIS WILL NOT WORK:\nconst fs = require('fs');\n\ntry {\n fs.readFile('/some/file/that/does-not-exist', (err, data) => {\n // mistaken assumption: throwing here...\n if (err) {\n throw err;\n }\n });\n} catch (err) {\n // This will not catch the throw!\n console.error(err);\n}\nThis will not work because the callback function passed to fs.readFile() is\ncalled asynchronously. By the time the callback has been called, the\nsurrounding code (including the try { } catch (err) { } block will have\nalready exited. Throwing an error inside the callback can crash the Node.js\nprocess in most cases. If domains are enabled, or a handler has been\nregistered with process.on('uncaughtException'), such errors can be\nintercepted.
A JavaScript exception is a value that is thrown as a result of an invalid\noperation or as the target of a throw statement. While it is not required\nthat these values are instances of Error or classes which inherit from\nError, all exceptions thrown by Node.js or the JavaScript runtime will be\ninstances of Error.
Some exceptions are unrecoverable at the JavaScript layer. Such exceptions\nwill always cause the Node.js process to crash. Examples include assert()\nchecks or abort() calls in the C++ layer.
System errors are generated when exceptions occur within the program's\nruntime environment. Typically, these are operational errors that occur\nwhen an application violates an operating system constraint such as attempting\nto read a file that does not exist or when the user does not have sufficient\npermissions.
\nSystem errors are typically generated at the syscall level: an exhaustive list\nof error codes and their meanings is available by running man 2 intro or\nman 3 errno on most Unices; or online.
In Node.js, system errors are represented as augmented Error objects with\nadded properties.
The error.code property is a string representing the error code, which is\ntypically E followed by a sequence of capital letters.
The error.errno property is a number or a string.\nThe number is a negative value which corresponds to the error code defined\nin libuv Error handling. See uv-errno.h header file\n(deps/uv/include/uv-errno.h in the Node.js source tree) for details. In case\nof a string, it is the same as error.code.
The error.syscall property is a string describing the syscall that failed.
When present (e.g. in fs or child_process), the error.path property is a\nstring containing a relevant invalid pathname.
When present (e.g. in net or dgram), the error.address property is a\nstring describing the address to which the connection failed.
When present (e.g. in net or dgram), the error.port property is a number\nrepresenting the connection's port that is not available.
This list is not exhaustive, but enumerates many of the common system\nerrors encountered when writing a Node.js program. An exhaustive list may be\nfound here.
\nEACCES (Permission denied): An attempt was made to access a file in a way\nforbidden by its file access permissions.
EADDRINUSE (Address already in use): An attempt to bind a server\n(net, http, or https) to a local address failed due to\nanother server on the local system already occupying that address.
ECONNREFUSED (Connection refused): No connection could be made because the\ntarget machine actively refused it. This usually results from trying to\nconnect to a service that is inactive on the foreign host.
ECONNRESET (Connection reset by peer): A connection was forcibly closed by\na peer. This normally results from a loss of the connection on the remote\nsocket due to a timeout or reboot. Commonly encountered via the http\nand net modules.
EEXIST (File exists): An existing file was the target of an operation that\nrequired that the target not exist.
EISDIR (Is a directory): An operation expected a file, but the given\npathname was a directory.
EMFILE (Too many open files in system): Maximum number of\nfile descriptors allowable on the system has been reached, and\nrequests for another descriptor cannot be fulfilled until at least one\nhas been closed. This is encountered when opening many files at once in\nparallel, especially on systems (in particular, macOS) where there is a low\nfile descriptor limit for processes. To remedy a low limit, run\nulimit -n 2048 in the same shell that will run the Node.js process.
ENOENT (No such file or directory): Commonly raised by fs operations\nto indicate that a component of the specified pathname does not exist -- no\nentity (file or directory) could be found by the given path.
ENOTDIR (Not a directory): A component of the given pathname existed, but\nwas not a directory as expected. Commonly raised by fs.readdir.
ENOTEMPTY (Directory not empty): A directory with entries was the target\nof an operation that requires an empty directory -- usually fs.unlink.
EPERM (Operation not permitted): An attempt was made to perform an\noperation that requires elevated privileges.
EPIPE (Broken pipe): A write on a pipe, socket, or FIFO for which there is\nno process to read the data. Commonly encountered at the net and\nhttp layers, indicative that the remote side of the stream being\nwritten to has been closed.
ETIMEDOUT (Operation timed out): A connect or send request failed because\nthe connected party did not properly respond after a period of time. Usually\nencountered by http or net -- often a sign that a socket.end()\nwas not properly called.
Used generically to identify that an iterable argument (i.e. a value that works\nwith for...of loops) is required, but not provided to a Node.js API.
Used by the util.callbackify() API when a callbackified Promise is rejected\nwith a falsy value (e.g. null).
Used when headers have already been sent and another attempt is made to add\nmore headers.
\n\n", "type": "module", "displayName": "ERR_HTTP_HEADERS_SENT" }, { "textRaw": "ERR_HTTP_INVALID_STATUS_CODE", "name": "err_http_invalid_status_code", "desc": "Used for status codes outside the regular status code ranges (100-999).
\n\n", "type": "module", "displayName": "ERR_HTTP_INVALID_STATUS_CODE" }, { "textRaw": "ERR_HTTP_TRAILER_INVALID", "name": "err_http_trailer_invalid", "desc": "Used when the Trailer header is set even though the transfer encoding does not\nsupport that.
For HTTP/2 requests using the CONNECT method, the :authority pseudo-header\nis required.
For HTTP/2 requests using the CONNECT method, the :path pseudo-header is\nforbidden.
The HTTP/2 requests using the CONNECT method, the :scheme pseudo-header is\nforbidden.
A non-specific HTTP/2 error has occurred.
\n\n", "type": "module", "displayName": "ERR_HTTP2_ERROR" }, { "textRaw": "ERR_HTTP2_FRAME_ERROR", "name": "err_http2_frame_error", "desc": "Used when a failure occurs sending an individual frame on the HTTP/2\nsession.
\n\n", "type": "module", "displayName": "ERR_HTTP2_FRAME_ERROR" }, { "textRaw": "ERR_HTTP2_HEADERS_OBJECT", "name": "err_http2_headers_object", "desc": "Used when an HTTP/2 Headers Object is expected.
\n\n", "type": "module", "displayName": "ERR_HTTP2_HEADERS_OBJECT" }, { "textRaw": "ERR_HTTP2_HEADERS_SENT", "name": "err_http2_headers_sent", "desc": "Used when an attempt is made to send multiple response headers.
\n\n", "type": "module", "displayName": "ERR_HTTP2_HEADERS_SENT" }, { "textRaw": "ERR_HTTP2_HEADER_SINGLE_VALUE", "name": "err_http2_header_single_value", "desc": "Used when multiple values have been provided for an HTTP header field that\nrequired to have only a single value.
\n\n", "type": "module", "displayName": "ERR_HTTP2_HEADER_SINGLE_VALUE" }, { "textRaw": "ERR_HTTP2_INFO_HEADERS_AFTER_RESPOND", "name": "err_http2_info_headers_after_respond", "desc": "HTTP/2 Informational headers must only be sent prior to calling the\nHttp2Stream.prototype.respond() method.
Informational HTTP status codes (1xx) may not be set as the response status\ncode on HTTP/2 responses.
HTTP/1 connection specific headers are forbidden to be used in HTTP/2\nrequests and responses.
\n\n", "type": "module", "displayName": "ERR_HTTP2_INVALID_CONNECTION_HEADERS" }, { "textRaw": "ERR_HTTP2_INVALID_HEADER_VALUE", "name": "err_http2_invalid_header_value", "desc": "Used to indicate that an invalid HTTP/2 header value has been specified.
\n\n", "type": "module", "displayName": "ERR_HTTP2_INVALID_HEADER_VALUE" }, { "textRaw": "ERR_HTTP2_INVALID_INFO_STATUS", "name": "err_http2_invalid_info_status", "desc": "An invalid HTTP informational status code has been specified. Informational\nstatus codes must be an integer between 100 and 199 (inclusive).
Input Buffer and Uint8Array instances passed to the\nhttp2.getUnpackedSettings() API must have a length that is a multiple of\nsix.
Only valid HTTP/2 pseudoheaders (:status, :path, :authority, :scheme,\nand :method) may be used.
Used when any action is performed on an Http2Session object that has already\nbeen destroyed.
An invalid value has been specified for an HTTP/2 setting.
\n\n", "type": "module", "displayName": "ERR_HTTP2_INVALID_SETTING_VALUE" }, { "textRaw": "ERR_HTTP2_INVALID_STREAM", "name": "err_http2_invalid_stream", "desc": "Used when an operation has been performed on a stream that has already been\ndestroyed.
\n\n", "type": "module", "displayName": "ERR_HTTP2_INVALID_STREAM" }, { "textRaw": "ERR_HTTP2_MAX_PENDING_SETTINGS_ACK", "name": "err_http2_max_pending_settings_ack", "desc": "Whenever an HTTP/2 SETTINGS frame is sent to a connected peer, the peer is\nrequired to send an acknowledgement that it has received and applied the new\nSETTINGS. By default, a maximum number of un-acknowledged SETTINGS frame may\nbe sent at any given time. This error code is used when that limit has been\nreached.
Used when the maximum number of streams on a single HTTP/2 session have been\ncreated.
\n\n", "type": "module", "displayName": "ERR_HTTP2_OUT_OF_STREAMS" }, { "textRaw": "ERR_HTTP2_PAYLOAD_FORBIDDEN", "name": "err_http2_payload_forbidden", "desc": "Used when a message payload is specified for an HTTP response code for which\na payload is forbidden.
\n\n", "type": "module", "displayName": "ERR_HTTP2_PAYLOAD_FORBIDDEN" }, { "textRaw": "ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED", "name": "err_http2_pseudoheader_not_allowed", "desc": "Used to indicate that an HTTP/2 pseudo-header has been used inappropriately.\nPseudo-headers are header key names that begin with the : prefix.
Used when push streams have been disabled by the client but an attempt to\ncreate a push stream is made.
\n\n", "type": "module", "displayName": "ERR_HTTP2_PUSH_DISABLED" }, { "textRaw": "ERR_HTTP2_SEND_FILE", "name": "err_http2_send_file", "desc": "Used when an attempt is made to use the\nHttp2Stream.prototype.responseWithFile() API to send a non-regular file.
Used when an attempt is made to connect a Http2Session object to a\nnet.Socket or tls.TLSSocket that has already been bound to another\nHttp2Session object.
Use of the 101 Informational status code is forbidden in HTTP/2.
An invalid HTTP status code has been specified. Status codes must be an integer\nbetween 100 and 599 (inclusive).
Used when an action has been performed on an HTTP/2 Stream that has already\nbeen closed.
\n\n", "type": "module", "displayName": "ERR_HTTP2_STREAM_CLOSED" }, { "textRaw": "ERR_HTTP2_STREAM_ERROR", "name": "err_http2_stream_error", "desc": "Used when a non-zero error code has been specified in an RST_STREAM frame.
When setting the priority for an HTTP/2 stream, the stream may be marked as\na dependency for a parent stream. This error code is used when an attempt is\nmade to mark a stream and dependent of itself.
\n\n", "type": "module", "displayName": "ERR_HTTP2_STREAM_SELF_DEPENDENCY" }, { "textRaw": "ERR_HTTP2_UNSUPPORTED_PROTOCOL", "name": "err_http2_unsupported_protocol", "desc": "Used when http2.connect() is passed a URL that uses any protocol other than\nhttp: or https:.
Used when a given index is out of the accepted range (e.g. negative offsets).
\n\n", "type": "module", "displayName": "ERR_INDEX_OUT_OF_RANGE" }, { "textRaw": "ERR_INVALID_ARG_TYPE", "name": "err_invalid_arg_type", "desc": "Used generically to identify that an argument of the wrong type has been passed\nto a Node.js API.
\n\n", "type": "module", "displayName": "ERR_INVALID_ARG_TYPE" }, { "textRaw": "ERR_INVALID_CALLBACK", "name": "err_invalid_callback", "desc": "Used generically to identify that a callback function is required and has not\nbeen provided to a Node.js API.
\n\n", "type": "module", "displayName": "ERR_INVALID_CALLBACK" }, { "textRaw": "ERR_INVALID_FILE_URL_HOST", "name": "err_invalid_file_url_host", "desc": "Used when a Node.js API that consumes file: URLs (such as certain functions in\nthe fs module) encounters a file URL with an incompatible host. Currently,\nthis situation can only occur on Unix-like systems, where only localhost or an\nempty host is supported.
Used when a Node.js API that consumes file: URLs (such as certain\nfunctions in the fs module) encounters a file URL with an incompatible\npath. The exact semantics for determining whether a path can be used is\nplatform-dependent.
Used when an attempt is made to send an unsupported "handle" over an IPC\ncommunication channel to a child process. See subprocess.send() and\nprocess.send() for more information.
Used generically to identify when an invalid or unexpected value has been\npassed in an options object.
\n\n", "type": "module", "displayName": "ERR_INVALID_OPT_VALUE" }, { "textRaw": "ERR_INVALID_PROTOCOL", "name": "err_invalid_protocol", "desc": "Used when an invalid options.protocol is passed.
Used when a Buffer, Uint8Array or string is provided as stdio input to a\nsynchronous fork. See the documentation for the\nchild_process module for more information.
Used generically to identify that a Node.js API function is called with an\nincompatible this value.
Example:
\nconst { URLSearchParams } = require('url');\nconst urlSearchParams = new URLSearchParams('foo=bar&baz=new');\n\nconst buf = Buffer.alloc(1);\nurlSearchParams.has.call(buf, 'foo');\n// Throws a TypeError with code 'ERR_INVALID_THIS'\nUsed when an element in the iterable provided to the WHATWG URLSearchParams constructor does not\nrepresent a [name, value] tuple – that is, if an element is not iterable, or\ndoes not consist of exactly two elements.
Used when an invalid URL is passed to the WHATWG\nURL constructor to be parsed. The thrown error object\ntypically has an additional property 'input' that contains the URL that failed\nto parse.
Used generically to signify an attempt to use a URL of an incompatible scheme\n(aka protocol) for a specific purpose. It is currently only used in the\nWHATWG URL API support in the fs module (which only accepts URLs with\n'file' scheme), but may be used in other Node.js APIs as well in the future.
Used when an attempt is made to use an IPC communication channel that has\nalready been closed.
\n\n", "type": "module", "displayName": "ERR_IPC_CHANNEL_CLOSED" }, { "textRaw": "ERR_IPC_DISCONNECTED", "name": "err_ipc_disconnected", "desc": "Used when an attempt is made to disconnect an already disconnected IPC\ncommunication channel between two Node.js processes. See the documentation for\nthe child_process module for more information.
Used when an attempt is made to create a child Node.js process using more than\none IPC communication channel. See the documentation for the\nchild_process module for more information.
Used when an attempt is made to open an IPC communication channel with a\nsynchronous forked Node.js process. See the documentation for the\nchild_process module for more information.
Used when a required argument of a Node.js API is not passed. This is currently\nonly used in the WHATWG URL API for strict compliance with the specification\n(which in some cases may accept func(undefined) but not func()). In most\nnative Node.js APIs, func(undefined) and func() are treated identically, and\nthe ERR_INVALID_ARG_TYPE error code may be used instead.
Used when an attempt is made to use features that require ICU, while\nNode.js is not compiled with ICU support.
\n\n", "type": "module", "displayName": "ERR_NO_ICU" }, { "textRaw": "ERR_SOCKET_ALREADY_BOUND", "name": "err_socket_already_bound", "desc": "Used when an attempt is made to bind a socket that has already been bound.
\n\n", "type": "module", "displayName": "ERR_SOCKET_ALREADY_BOUND" }, { "textRaw": "ERR_SOCKET_BAD_PORT", "name": "err_socket_bad_port", "desc": "Used when an API function expecting a port > 0 and < 65536 receives an invalid\nvalue.
\n\n", "type": "module", "displayName": "ERR_SOCKET_BAD_PORT" }, { "textRaw": "ERR_SOCKET_BAD_TYPE", "name": "err_socket_bad_type", "desc": "Used when an API function expecting a socket type (udp4 or udp6) receives an\ninvalid value.
Used when data cannot be sent on a socket.
\n\n", "type": "module", "displayName": "ERR_SOCKET_CANNOT_SEND" }, { "textRaw": "ERR_SOCKET_DGRAM_NOT_RUNNING", "name": "err_socket_dgram_not_running", "desc": "Used when a call is made and the UDP subsystem is not running.
\n\n", "type": "module", "displayName": "ERR_SOCKET_DGRAM_NOT_RUNNING" }, { "textRaw": "ERR_STDERR_CLOSE", "name": "err_stderr_close", "desc": "Used when an attempt is made to close the process.stderr stream. By design,\nNode.js does not allow stdout or stderr Streams to be closed by user code.
Used when an attempt is made to close the process.stdout stream. By design,\nNode.js does not allow stdout or stderr Streams to be closed by user code.
Used to identify a specific kind of internal Node.js error that should not\ntypically be triggered by user code. Instances of this error point to an\ninternal bug within the Node.js binary itself.
\n\n", "type": "module", "displayName": "ERR_UNKNOWN_BUILTIN_MODULE" }, { "textRaw": "ERR_UNKNOWN_SIGNAL", "name": "err_unknown_signal", "desc": "Used when an invalid or unknown process signal is passed to an API expecting a\nvalid signal (such as subprocess.kill()).
Used when an attempt is made to launch a Node.js process with an unknown stdin\nfile type. Errors of this kind cannot typically be caused by errors in user\ncode, although it is not impossible. Occurrences of this error are most likely\nan indication of a bug within Node.js itself.
Used when an attempt is made to launch a Node.js process with an unknown\nstdout or stderr file type. Errors of this kind cannot typically be caused\nby errors in user code, although it is not impossible. Occurrences of this error\nare most likely an indication of a bug within Node.js itself.
Used when the V8 BreakIterator API is used but the full ICU data set is not\ninstalled.
\n\n", "type": "module", "displayName": "ERR_V8BREAKITERATOR" }, { "textRaw": "ERR_VALID_PERFORMANCE_ENTRY_TYPE", "name": "err_valid_performance_entry_type", "desc": "Used by the Performance Timing API (perf_hooks) when no valid performance\nentry types were found.
Used when a given value is out of the accepted range.
\n", "type": "module", "displayName": "ERR_VALUE_OUT_OF_RANGE" } ], "type": "misc", "displayName": "Node.js Error Codes" } ], "classes": [ { "textRaw": "Class: Error", "type": "class", "name": "Error", "desc": "A generic JavaScript Error object that does not denote any specific\ncircumstance of why the error occurred. Error objects capture a "stack trace"\ndetailing the point in the code at which the Error was instantiated, and may\nprovide a text description of the error.
All errors generated by Node.js, including all System and JavaScript errors,\nwill either be instances of, or inherit from, the Error class.
Creates a .stack property on targetObject, which when accessed returns\na string representing the location in the code at which\nError.captureStackTrace() was called.
const myObject = {};\nError.captureStackTrace(myObject);\nmyObject.stack; // similar to `new Error().stack`\nThe first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.
The optional constructorOpt argument accepts a function. If given, all frames\nabove constructorOpt, including constructorOpt, will be omitted from the\ngenerated stack trace.
The constructorOpt argument is useful for hiding implementation\ndetails of error generation from an end user. For instance:
function MyError() {\n Error.captureStackTrace(this, MyError);\n}\n\n// Without passing MyError to captureStackTrace, the MyError\n// frame would show up in the .stack property. By passing\n// the constructor, we omit that frame, and retain all frames below it.\nnew MyError().stack;\nThe Error.stackTraceLimit property specifies the number of stack frames\ncollected by a stack trace (whether generated by new Error().stack or\nError.captureStackTrace(obj)).
The default value is 10 but may be set to any valid JavaScript number. Changes\nwill 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\nnot capture any frames.
\n" }, { "textRaw": "`code` {string} ", "type": "string", "name": "code", "desc": "The error.code property is a string label that identifies the kind of error.\nSee Node.js Error Codes for details about specific codes.
The error.message property is the string description of the error as set by\ncalling new Error(message). The message passed to the constructor will also\nappear in the first line of the stack trace of the Error, however changing\nthis property after the Error object is created may not change the first\nline of the stack trace (for example, when error.stack is read before this\nproperty is changed).
const err = new Error('The message');\nconsole.error(err.message);\n// Prints: The message\nThe error.stack property is a string describing the point in the code at which\nthe Error was instantiated.
For example:
\nError: Things keep happening!\n at /home/gbusey/file.js:525:2\n at Frobnicator.refrobulate (/home/gbusey/business-logic.js:424:21)\n at Actor.<anonymous> (/home/gbusey/actors.js:400:8)\n at increaseSynergy (/home/gbusey/actors.js:701:6)\nThe first line is formatted as <error class name>: <error message>, and\nis followed by a series of stack frames (each line beginning with "at ").\nEach frame describes a call site within the code that lead to the error being\ngenerated. V8 attempts to display a name for each function (by variable name,\nfunction name, or object method name), but occasionally it will not be able to\nfind a suitable name. If V8 cannot determine a name for the function, only\nlocation information will be displayed for that frame. Otherwise, the\ndetermined function name will be displayed with location information appended\nin parentheses.
It is important to note that frames are only generated for JavaScript\nfunctions. If, for example, execution synchronously passes through a C++ addon\nfunction called cheetahify, which itself calls a JavaScript function, the\nframe representing the cheetahify call will not be present in the stack\ntraces:
const cheetahify = require('./native-binding.node');\n\nfunction makeFaster() {\n // cheetahify *synchronously* calls speedy.\n cheetahify(function speedy() {\n throw new Error('oh no!');\n });\n}\n\nmakeFaster();\n// will throw:\n// /home/gbusey/file.js:6\n// throw new Error('oh no!');\n// ^\n// Error: oh no!\n// at speedy (/home/gbusey/file.js:6:11)\n// at makeFaster (/home/gbusey/file.js:5:3)\n// at Object.<anonymous> (/home/gbusey/file.js:10:1)\n// at Module._compile (module.js:456:26)\n// at Object.Module._extensions..js (module.js:474:10)\n// at Module.load (module.js:356:32)\n// at Function.Module._load (module.js:312:12)\n// at Function.Module.runMain (module.js:497:10)\n// at startup (node.js:119:16)\n// at node.js:906:3\nThe location information will be one of:
\nnative, if the frame represents a call internal to V8 (as in [].forEach).plain-filename.js:line:column, if the frame represents a call internal\n to Node.js./absolute/path/to/file.js:line:column, if the frame represents a call in\na user program, or its dependencies.The string representing the stack trace is lazily generated when the\nerror.stack property is accessed.
The number of frames captured by the stack trace is bounded by the smaller of\nError.stackTraceLimit or the number of available frames on the current event\nloop tick.
System-level errors are generated as augmented Error instances, which are\ndetailed here.
Creates a new Error object and sets the error.message property to the\nprovided text message. If an object is passed as message, the text message\nis generated by calling message.toString(). The error.stack property will\nrepresent the point in the code at which new Error() was called. Stack traces\nare dependent on V8's stack trace API. Stack traces extend only to either\n(a) the beginning of synchronous code execution, or (b) the number of frames\ngiven by the property Error.stackTraceLimit, whichever is smaller.
Creates a new Error object and sets the error.message property to the\nprovided text message. If an object is passed as message, the text message\nis generated by calling message.toString(). The error.stack property will\nrepresent the point in the code at which new Error() was called. Stack traces\nare dependent on V8's stack trace API. Stack traces extend only to either\n(a) the beginning of synchronous code execution, or (b) the number of frames\ngiven by the property Error.stackTraceLimit, whichever is smaller.
A subclass of Error that indicates the failure of an assertion. Such errors\ncommonly indicate inequality of actual and expected value.
For example:
\nassert.strictEqual(1, 2);\n// AssertionError [ERR_ASSERTION]: 1 === 2\nA subclass of Error that indicates that a provided argument was not within the\nset or range of acceptable values for a function; whether that is a numeric\nrange, or outside the set of options for a given function parameter.
For example:
\nrequire('net').connect(-1);\n// throws "RangeError: "port" option should be >= 0 and < 65536: -1"\nNode.js will generate and throw RangeError instances immediately as a form\nof argument validation.
A subclass of Error that indicates that an attempt is being made to access a\nvariable that is not defined. Such errors commonly indicate typos in code, or\nan otherwise broken program.
While client code may generate and propagate these errors, in practice, only V8\nwill do so.
\ndoesNotExist;\n// throws ReferenceError, doesNotExist is not a variable in this program.\nUnless an application is dynamically generating and running code,\nReferenceError instances should always be considered a bug in the code\nor its dependencies.
A subclass of Error that indicates that a program is not valid JavaScript.\nThese errors may only be generated and propagated as a result of code\nevaluation. Code evaluation may happen as a result of eval, Function,\nrequire, or vm. These errors are almost always indicative of a broken\nprogram.
try {\n require('vm').runInThisContext('binary ! isNotOk');\n} catch (err) {\n // err will be a SyntaxError\n}\nSyntaxError instances are unrecoverable in the context that created them –\nthey may only be caught by other contexts.
A subclass of Error that indicates that a provided argument is not an\nallowable type. For example, passing a function to a parameter which expects a\nstring would be considered a TypeError.
require('url').parse(() => { });\n// throws TypeError, since it expected a string\nNode.js will generate and throw TypeError instances immediately as a form\nof argument validation.