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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`](https://nodejs.org/api/vm.html).

# Example



```js
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

```bash
npm install is-error-instance
```

This package works in both Node.js >=18.18.0 and
[browsers](https://raw.githubusercontent.com/ehmicky/dev-tasks/main/src/browserslist).

This is an ES module. It must be loaded using
[an `import` or `import()` statement](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c),
not `require()`. If TypeScript is used, it must be configured to
[output ES modules](https://www.typescriptlang.org/docs/handbook/esm-node.html),
not CommonJS.

# API

## isErrorInstance(value)

`value` `any`\
_Return value_: `boolean`

# Related projects

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

# Support

For any question, _don't hesitate_ to [submit an issue on GitHub](../../issues).

Everyone is welcome regardless of personal background. We enforce a
[Code of conduct](CODE_OF_CONDUCT.md) 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](CONTRIBUTING.md). Pull requests are welcome!







