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Properly create error classes.
Useful utilities when creating custom error classes.
- Ponyfill
error.causeon older Node.js and browsers - Properly set
error.name - Fix issues when
Errorhas been polyfilled
import { ensureCorrectClass, ponyfillCause, setErrorName, } from 'error-class-utils' export class CustomError extends Error { constructor(message, parameters) { super(message, parameters) // Fix some issues when `Error` has been polyfilled ensureCorrectClass(this, new.target) // Ponyfill `error.cause` on old Node.js/browsers ponyfillCause(this, parameters) } } // Properly set `error.name` as a non-enumerable and inherited property setErrorName(CustomError, 'CustomError')
import { CustomError } from './errors.js' const cause = new Error('innerMessage') const error = new CustomError('message', { cause }) console.log(error instanceof CustomError) // true console.log(error.name) // 'CustomError' console.log(error.cause) // Error: innerMessage ...
npm install error-class-utils
This package works in both Node.js >=18.18.0 and browsers.
This is an ES module. It must be loaded using
an import or import() statement,
not require(). If TypeScript is used, it must be configured to
output ES modules,
not CommonJS.
error Error
new.target typeof Error
Return value: void
Some Error polyfills (such as
es-shims/error-cause) prevent
extending from it. This fixes it.
The second argument must be
new.target.
This must be called directly inside a class constructor, after
super(message, parameters).
import { ensureCorrectClass } from 'error-class-utils' class CustomError extends Error { constructor(message, parameters) { super(message, parameters) ensureCorrectClass(this, new.target) } } // Thanks to `ensureCorrectClass()`, this is now always true even when // `Error` has been polyfilled console.log(new CustomError('message') instanceof CustomError) // true
error Error
parameters ErrorParams?
Return value: void
Ponyfills
error.cause
on
older Node.js and browsers.
This must be called inside a class constructor, after
super(message, parameters).
import { ponyfillCause } from 'error-class-utils' class CustomError extends Error { constructor(message, parameters) { super(message, parameters) ponyfillCause(this, parameters) } } try { throw new Error('innerMessage') } catch (cause) { // Works on any platforms thanks to ponyfill const error = new CustomError('message', { cause }) console.log(error.cause.message) // 'innerMessage' }
ErrorClass typeof Error
name string
Return value: void
Set an ErrorClass's
name.
This must be performed on an error class, not instance. Unlike setting
this.name = '...' inside an error's constructor, this follows the native
Error classes' pattern where error.name:
- Ends with the
Errorsuffix - Matches the
constructor's
name - Is inherited
- Is non-enumerable
import { setErrorName } from 'error-class-utils' class CustomError extends Error {} setErrorName(CustomError, 'CustomError') console.log(CustomError.name) // 'CustomError' console.log(CustomError.prototype.name) // 'CustomError' const error = new CustomError('message') console.log(error.name) // 'CustomError' console.log(Object.keys(error).includes('name')) // false
modern-errors: Handle errors in a simple, stable, consistent wayerror-custom-class: Create one error classerror-serializer: Convert errors to/from plain objectsnormalize-exception: Normalize exceptions/errorsis-error-instance: Check if a value is anErrorinstancemerge-error-cause: Merge an error with itscauseset-error-class: Properly update an error's classset-error-message: Properly update an error's messagewrap-error-message: Properly wrap an error's messageset-error-props: Properly update an error's propertiesset-error-stack: Properly update an error's stackerror-cause-polyfill: Polyfillerror.causehandle-cli-error: π£ Error handler for CLI applications π₯beautiful-error: Prettify error messages and stackslog-process-errors: Show some β€ to Node.js process errorserror-http-response: Create HTTP error responseswinston-error-format: Log errors with Winston
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