Package Exports

error-serializer

Readme

Convert errors to/from plain objects.

Features

Ensures errors are safe to serialize with JSON
Custom serialization logic (e.g. YAML or process.send())
Keeps both native (TypeError, etc.) and custom error types
Preserves errors' additional properties
Works recursively with error.cause and AggregateError
Normalizes invalid errors
Safe: this never throws

Example

import { serialize, parse } from 'error-serializer'

const error = new TypeError('example')
const errorObject = serialize(error)
// Plain object: { name: 'TypeError', message: 'example', stack: '...' }

const errorString = JSON.serialize(errorObject)
const newErrorObject = JSON.parse(errorString)

const newError = parse(newErrorObject)
// Error instance: 'TypeError: example ...'

Install

npm install error-serializer

This package is an ES module and must be loaded using an import or import() statement, not require().

API

serialize(errorInstance)

errorInstance any
Return value: object

Convert an Error instance into a plain object.

parse(errorObject, options?)

errorObject any
options Options?
Return value: Error

Convert an error plain object into an Error instance.

Options

Object with the following optional properties.

types

Type: object

Custom error types to keep when parsing.

Each key is an errorObject.name.
Each value is the error type to use. The constructor will be called with a single message argument. It it throws, Error will be used as the error type instead.

const errorObject = serialize(new CustomError('example'))
// `CustomError` type is kept
const error = parse(errorObject, { types: { CustomError } })
// Map `CustomError` to another type
const otherError = parse(errorObject, { types: { CustomError: TypeError } })

Usage

JSON safety

Error plain objects are always safe to serialize with JSON.

const error = new Error('example')
error.cycle = error

// Cycles make `JSON.serialize()` throw, so they are removed
console.log(serialize(error).cycle) // {}

Custom serialization

serialize() returns a plain object, not a string. This allows any serialization logic to be performed.

import { dump } from 'js-yaml'

const error = new Error('example')
const errorObject = serialize(error)
const errorYamlString = dump(errorObject)
// name: Error
// message: example
// stack: Error: example ...

Additional error properties

const error = new TypeError('example')
error.prop = true

const errorObject = serialize(error)
console.log(errorObject.prop) // true
const newError = parse(errorObject)
console.log(newError.prop) // true

`error.cause` and `AggregateError`

const innerErrors = [new Error('one'), new Error('two')]
const cause = new Error('three')
const error = new AggregateError(innerErrors, 'four', { cause })

const errorObject = serialize(error)
// {
//   name: 'AggregateError',
//   message: 'four',
//   stack: '...',
//   cause: { name: 'Error', message: 'three', stack: '...' },
//   errors: [{ name: 'Error', message: 'one', stack: '...' }, ...],
// }
const newError = parse(errorObject)
// AggregateError: four
//   [cause]: Error: three
//   [errors]: [Error: one, Error: two]

Error normalization

Invalid error instances or objects are normalized.

// Normalizes invalid error: not an `Error` instance
console.log(serialize('example')) // { name: 'Error', message: 'example', ... }

// Normalizes `error.message`: not a string
console.log(parse({ message: false })) // Error: false

modern-errors: Handle errors like it's 2022 🔮
error-type: Create custom error types
normalize-exception: Normalize exceptions/errors
merge-error-cause: Merge an error with its cause
error-cause-polyfill: Polyfill error.cause
handle-cli-error: 💣 Error handler for CLI applications 💥
safe-json-value: ⛑️ JSON serialization should never fail

Support

For any question, don't hesitate to submit an issue on GitHub.

Everyone is welcome regardless of personal background. We enforce a Code of conduct in order to promote a positive and inclusive environment.

Contributing

This project was made with ❤️. The simplest way to give back is by starring and sharing it online.

If the documentation is unclear or has a typo, please click on the page's Edit button (pencil icon) and suggest a correction.

If you would like to help us fix a bug or add a new feature, please check our guidelines. Pull requests are welcome!

error-serializer