set-error-props

Properly update an error's properties.

Features

• Prevents overriding error core properties (name, message, etc.)
• Protects against prototype pollution
• Merges deeply
• Merges with either high or low priority
• Copies another error's properties
• Strict, deep TypeScript typing of the return value
• Handles invalid errors

Examples

Error core properties

import setErrorProps from 'set-error-props'

const error = new Error('one')
setErrorProps(error, { message: 'two' })
console.log(error.message) // 'one'

Prototype pollution

const error = new Error('one')
setErrorProps(error, { toString: () => 'injected' })
console.log(error.toString()) // 'Error: one'
console.log(Error.prototype.toString()) // 'Error'

Deep merging

// Deep merges plain objects and arrays
const error = new Error('message')
error.prop = { one: [true] }
setErrorProps(error, { prop: { one: [false], two: true } })
console.log(error.prop) // { one: [true, false], two: true }

Low priority merging

const error = new Error('message')
error.prop = { one: true }
setErrorProps(error, { prop: { one: false, two: true } }, { lowPriority: true })
console.log(error.prop) // { one: true, two: true }

Error copy

const error = new Error('one')
const secondError = new Error('two')
secondError.prop = true
setErrorProps(error, secondError)
console.log(error.message) // 'one'
console.log(error.prop) // true

Invalid errors

try {
  throw 'not_an_error_instance'
} catch (error) {
  setErrorProps(error, { prop: true }) // Converted to an error instance
}

Install

npm install set-error-props

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

API

setErrorProps(error, props, options?)

error Error | unknown
props Error | object
options Options?
Return value: Error

Assigns props to error, then returns error. If error is not an Error instance, it is converted to one.

Options

Optional object with the following properties.

lowPriority

Type: boolean
Default: false

Whether props should have lower merging priority over error or not.

Related projects

• modern-errors: Handle errors like it's 2022 🔮
• error-custom-classes: Create multiple error classes
• error-custom-class: Create one error class
• error-serializer: Convert errors to/from plain objects
• 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 💥
• log-process-errors: Show some ❤ to Node.js process errors

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!

Changelog

1.1.0

Features

• Normalize and return error
• Validate arguments
• Improve TypeScript types