Universal API for creating Node.js errors

• 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]>
  • SystemCode
  • SystemErrorMap
• Contribute

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

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.

This package is ESM only.

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

yarn add @flex-development/errnode

See Git - Protocols | Yarn  for details regarding installing from Git.

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>

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'
}

This package exports the following identifiers:

• E
• codes
• determineSpecificType
• errors
  • 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_MODULE_SPECIFIER
  • ERR_INVALID_PACKAGE_CONFIG
  • ERR_INVALID_PACKAGE_TARGET
  • ERR_INVALID_RETURN_VALUE
  • ERR_INVALID_URL
  • ERR_METHOD_NOT_IMPLEMENTED
  • ERR_MISSING_OPTION
  • ERR_MODULE_NOT_FOUND
  • ERR_NETWORK_IMPORT_DISALLOWED
  • 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.

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 😉) to add a constructor. E can be used instead, however.

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.

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>

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

(NodeErrorConstructor) NodeError constructor.

Node.js error codes.

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

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

• value (unknown) — value to check

(string) specific type of value.

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

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

(string) formatted list.

Remove unnecessary frames from Node.js core errors.

• T (Fn) — function to wrap

• fn (T) — function to wrap

(T) the wrapped function.

Check if value is a NodeError.

• value (unknown) — value to check

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

System error codes.

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

This package is fully typed with TypeScript.

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>

Node.js exception object (TypeScript interface).

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

• Error

• 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

Build an error message.

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

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

(string) error message.

Node.js error constructor (TypeScript interface).

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

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

• prototype (T) — node.js error prototype

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
  }
}

Node.js error object (TypeScript interface).

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

• Error

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

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>

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
  }
}

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.