errnode

Universal API for creating Node.js errors

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • E
  • codes
  • determineSpecificType(value)
  • errors
  • formatList(list[, type])
  • hideStackFrames(fn)
  • isNodeError(value)
  • syscodes
• Types
  • Code
  • ErrnoException<[T]>
  • MessageFn<[T][, Args]>
  • NodeErrorConstructor<[T][, Args]>
  • NodeErrorMap
  • NodeError<[T]>
  • Stringifiable
  • SystemCode
  • SystemErrorMap
• Contribute

What is this?

This package provides a universal API for creating Node.js errors.

When should I use this?

This package is designed to help developers build ponyfills, as well as more verbose tools like mlly, by providing a set of utilities and constructor functions for creating Node.js errors.

Install

This package is ESM only.

In Node.js (version 18+) with yarn:

yarn add @flex-development/errnode

In Deno with esm.sh:

import { ERR_MODULE_NOT_FOUND } from 'https://esm.sh/@flex-development/errnode'

In browsers with esm.sh:

<script type="module">
  import { ERR_MODULE_NOT_FOUND } from 'https://esm.sh/@flex-development/errnode'
</script>

Use

Say we have the file example.mjs:

import { ERR_INVALID_ARG_TYPE, isNodeError } from '@flex-development/errnode'

/**
 * Ensure `value` is a string.
 *
 * @see {@linkcode ErrInvalidArgType}
 *
 * @param {unknown} value
 *  Value supplied by user
 * @param {string} name
 *  Name of invalid argument or property
 * @return {value is string}
 *  `true` if `value` is a string
 * @throws {import('@flex-development/errnode').ErrInvalidArgType}
 *  If `value` is not a string
 */
function validateString(value, name) {
  if (typeof value === 'string') return true
  throw new ERR_INVALID_ARG_TYPE(name, 'string', value)
}

try {
  validateString(null, 'path')
} catch (e) {
  console.log('isNodeError:', isNodeError(e))
  console.log('TypeError:', e instanceof TypeError, '\n')
  throw e
}

...running node example.mjs yields:

isNodeError: true
TypeError: true

file:///node_modules/@flex-development/errnode/dist/internal/stack-trace.mjs:9
  Error.captureStackTrace(error);
        ^

TypeError: The 'path' argument must be of type string. Received null
    at __node_internal_captureLargerStackTrace (file:///node_modules/@flex-development/errnode/dist/internal/stack-trace.mjs:9:9)
    at new NodeError (file:///node_modules/@flex-development/errnode/dist/e.mjs:50:45)
    at validateString (file:///example.mjs:19:9)
    at file:///example.mjs:23:3
    at ModuleJob.run (node:internal/modules/esm/module_job:234:25)
    at async ModuleLoader.import (node:internal/modules/esm/loader:473:24)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:123:5) {
  code: 'ERR_INVALID_ARG_TYPE'
}

API

This package exports the following identifiers:

• E
• codes
• determineSpecificType
• errors
  • ERR_ARG_NOT_ITERABLE
  • ERR_ENCODING_NOT_SUPPORTED
  • ERR_IMPORT_ASSERTION_TYPE_FAILED
  • ERR_IMPORT_ASSERTION_TYPE_MISSING
  • ERR_IMPORT_ASSERTION_TYPE_UNSUPPORTED
  • ERR_IMPORT_ATTRIBUTE_MISSING
  • ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE
  • ERR_IMPORT_ATTRIBUTE_UNSUPPORTED
  • ERR_INCOMPATIBLE_OPTION_PAIR
  • ERR_INVALID_ARG_TYPE
  • ERR_INVALID_ARG_VALUE
  • ERR_INVALID_FILE_URL_HOST
  • ERR_INVALID_FILE_URL_PATH
  • ERR_INVALID_MODULE_SPECIFIER
  • ERR_INVALID_PACKAGE_CONFIG
  • ERR_INVALID_PACKAGE_TARGET
  • ERR_INVALID_RETURN_VALUE
  • ERR_INVALID_THIS
  • ERR_INVALID_TUPLE
  • ERR_INVALID_URL_SCHEME
  • ERR_INVALID_URL
  • ERR_METHOD_NOT_IMPLEMENTED
  • ERR_MISSING_ARGS
  • ERR_MISSING_OPTION
  • ERR_MODULE_NOT_FOUND
  • ERR_NETWORK_IMPORT_DISALLOWED
  • ERR_NO_CRYPTO
  • ERR_NO_ICU
  • ERR_OPERATION_FAILED
  • ERR_PACKAGE_IMPORT_NOT_DEFINED
  • ERR_PACKAGE_PATH_NOT_EXPORTED
  • ERR_UNHANDLED_ERROR
  • ERR_UNKNOWN_BUILTIN_MODULE
  • ERR_UNKNOWN_ENCODING
  • ERR_UNKNOWN_FILE_EXTENSION
  • ERR_UNKNOWN_MODULE_FORMAT
  • ERR_UNSUPPORTED_DIR_IMPORT
  • ERR_UNSUPPORTED_ESM_URL_SCHEME
  • ERR_UNSUPPORTED_RESOLVE_REQUEST
• formatList
• hideStackFrames
• isNodeError
• syscodes

There is no default export.

Errors

Constructor functions representing Node.js error codes. Constructor arguments are used to build error messages.

Errors (and their types) can be imported individually:

import {
  ERR_INVALID_MODULE_SPECIFIER,
  ERR_INVALID_PACKAGE_CONFIG,
  ERR_INVALID_PACKAGE_TARGET,
  ERR_MODULE_NOT_FOUND,
  ERR_PACKAGE_IMPORT_NOT_DEFINED,
  ERR_PACKAGE_PATH_NOT_EXPORTED,
  ERR_UNSUPPORTED_DIR_IMPORT,
  type ErrInvalidModuleSpecifier,
  type ErrInvalidModuleSpecifierArgs,
  type ErrInvalidModuleSpecifierConstructor,
  type ErrInvalidPackageConfig,
  type ErrInvalidPackageConfigArgs,
  type ErrInvalidPackageConfigConstructor,
  type ErrInvalidPackageTarget,
  type ErrInvalidPackageTargetArgs,
  type ErrInvalidPackageTargetConstructor,
  type ErrModuleNotFound,
  type ErrModuleNotFoundArgs,
  type ErrModuleNotFoundConstructor,
  type ErrPackageImportNotDefined,
  type ErrPackageImportNotDefinedArgs,
  type ErrPackageImportNotDefinedConstructor,
  type ErrPackagePathNotExported,
  type ErrPackagePathNotExportedArgs,
  type ErrPackagePathNotExportedConstructor,
  type ErrUnsupportedDirImport,
  type ErrUnsupportedDirImportConstructor
 } from '@flex-development/errnode'

...or all at once using the errors export:

import { errors } from '@flex-development/errnode'

See the source code for documentation.

Note: This package does not export a constructor for every error. Submit a feature request (or pull request if you're up for the challenge :wink:) to add a constructor. E can be used instead, however.

E(code, Base, message)

Create a Node.js error constructor.

Constructor arguments are passed to format if the error message is a string, or message itself if it is a function. Message functions are also called with the new Node.js error instance as this.

Signatures

function E<T extends NodeErrorConstructor>(
  code: T['prototype']['code'],
  Base: ErrorConstructor,
  message: MessageFn<T['prototype'], Parameters<T>> | string
): T

function E<T extends NodeError, Args extends any[] = any[]>(
  code: T['code'],
  Base: ErrorConstructor,
  message: MessageFn<T, Args>
): NodeErrorConstructor<T, Args>

Parameters

• code (Code) — error code
• Base (ErrorConstructor) — base class
• message (MessageFn | string) — error message string or function

Returns

(NodeErrorConstructor) NodeError constructor.

codes

Node.js error codes.

See NODE_VERSIONS for a list of supported Node.js versions.

determineSpecificType(value)

Determine the specific type of a value for type-mismatch errors.

Parameters

• value (unknown) — value to check

Returns

(string) specific type of value.

formatList(list[, type])

Create a list string in the form 'A and B' or 'A, B, ..., and Z.

Parameters

• list (string | readonly string[]) — list to format
• type ('and' | 'or' | null | undefined, optional) — list transition type to insert before last element
  • default: 'and'

Returns

(string) formatted list.

hideStackFrames(fn)

Remove unnecessary frames from Node.js core errors.

Type Parameters

• T (Fn) — function to wrap

Parameters

• fn (T) — function to wrap

Returns

(T) the wrapped function.

isNodeError(value)

Check if value is a NodeError.

Parameters

• value (unknown) — value to check

Returns

(value is NodeError) true if value is NodeError, false otherwise.

syscodes

System error codes.

See NODE_VERSIONS for a list of supported Node.js versions.

Types

This package is fully typed with TypeScript.

Code

Union of registered codes that can occur where a node error code is expected (TypeScript type).

To register new codes, augment NodeErrorMap. They will be added to this union automatically.

type Code = Extract<keyof NodeErrorMap, string>

ErrnoException<[T]>

Node.js exception object (TypeScript interface).

Type Parameters

• T (SystemCode, optional) — system error code
  • default: SystemCode

Extends

• Error

Properties

• code (T) — system error code
• errno (number) — libuv error number
• message (string) — error message, always prefixed by syscall and code
• path? (string | undefined) — relevant invalid pathname
• syscall (string) — failed syscall description

MessageFn<[T][, Args]>

Build an error message.

Type Parameters

• T (NodeError, optional) — node error
  • default: NodeError
• Args (readonly any[], optional) — message arguments
  • default: any[]

Parameters

• this (T) — node error object
• ...args (Args) — message arguments

Returns

(string) error message.

NodeErrorConstructor<[T][, Args]>

Node.js error constructor (TypeScript interface).

Type Parameters

• T (NodeError, optional) — node error
  • default: NodeError
• Args (readonly any[], optional) — message arguments
  • default: any[]

Signatures

• new (...args: Args): T
• (...args: Args): T

Properties

• prototype (T) — node.js error prototype

NodeErrorMap

Registry of Node.js error codes (TypeScript interface).

When developing utilities that use more codes, augment NodeErrorMap to register those codes:

declare module '@flex-development/errnode' {
  interface NodeErrorMap {
    ERR_CUSTOM: true
  }
}

NodeError<[T]>

Node.js error object (TypeScript interface).

Type Parameters

• T (Code, optional) — error code
  • default: Code

Extends

• Error

Properties

• code (T) — error code
• toString (() => string) — get a string representation of the error

Stringifiable

A value with a toString method (TypeScript interface).

Properties

• toString (() => string) — get a string representation of the value

SystemCode

Union of registered codes that can occur where a system error code is expected (TypeScript type).

To register new codes, augment SystemErrorMap. They will be added to this union automatically.

type SystemCode = Extract<keyof SystemErrorMap, string>

SystemErrorMap

Registry of system error codes (TypeScript interface).

When developing utilities that use more codes, augment SystemErrorMap to register those codes:

declare module '@flex-development/errnode' {
  interface SystemErrorMap {
    ECUSTOM: true
  }
}

Contribute

See CONTRIBUTING.md.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.