Check if a value is an Error instance.

This is like value instanceof Error except it works across realms, such as iframes or Node.js vm.

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Example

import isErrorInstance from 'is-error-instance'

isErrorInstance(new Error('')) // true
isErrorInstance('') // false

const CrossRealmError = vm.runInNewContext('Error')
isErrorInstance(new CrossRealmError('')) // true

isErrorInstance(new TypeError('')) // true
isErrorInstance(new AnyOtherError('')) // true

isErrorInstance(new DOMException('')) // true
isErrorInstance(new DOMError('')) // true

isErrorInstance(new Proxy(new Error(''), {})) // true
isErrorInstance(
  new Proxy(new Error(''), {
    getPrototypeOf: () => {
      throw new Error('')
    },
  }),
) // false

Install

npm install is-error-instance

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

isErrorInstance(value)

value any
Return value: boolean

Related projects

• modern-errors: Handle errors in a simple, stable, consistent way
• error-custom-class: Create one error class
• error-class-utils: Utilities to properly create error classes
• error-serializer: Convert errors to/from plain objects
• merge-error-cause: Merge an error with its cause
• normalize-exception: Normalize exceptions/errors
• set-error-class: Properly update an error's class
• set-error-message: Properly update an error's message
• wrap-error-message: Properly wrap an error's message
• set-error-props: Properly update an error's properties
• set-error-stack: Properly update an error's stack
• error-cause-polyfill: Polyfill error.cause
• handle-cli-error: 💣 Error handler for CLI applications 💥
• log-process-errors: Show some ❤ to Node.js process errors
• error-http-response: Create HTTP error responses
• winston-error-format: Log errors with Winston

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

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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!