Set-error-class NPM

Properly update an error's class.

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Features

Sets an error's prototype, name and constructor
Update the error's stack with its new name
Handles invalid errors

Example

import setErrorClass from 'set-error-class'

const typeError = new TypeError('test')
console.log(typeError instanceof TypeError) // true
console.log(typeError.name) // 'TypeError'
console.log(typeError.constructor) // TypeError
console.log(typeError.stack) // TypeError: test ...

const rangeError = setErrorClass(typeError, RangeError)
console.log(rangeError === typeError) // true
console.log(rangeError instanceof RangeError) // true
console.log(rangeError.name) // 'RangeError'
console.log(rangeError.constructor) // RangeError
console.log(rangeError.stack) // RangeError: test ...

Install

npm install set-error-class

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.

API

setErrorClass(error, ErrorClass)

error Error | unknown\ ErrorClass typeof Error\ Return value: Error

Sets the error's prototype, name and constructor.

Usage

Invalid errors

error is returned. If error is not an Error instance, it is converted to one.

`error.stack`

In V8 (Chrome, Node.js, Deno, etc.), error.stack includes error.name. It is updated accordingly.

Error constructors

ErrorClass is assigned to error, but its constructor is not called. In some instances, this might lead to invalid errors. If ErrorClass's constructor is doing anything significant, that logic should be performed on error as well.