# check-error

> Error comparison and information related utility for node and the browser

Latest version **2.1.3** (published 2026-01-03) · MIT license · 0 weekly downloads

## Install

```sh
npm install check-error
pnpm add check-error
yarn add check-error
bun add check-error
```

## Health

**Score 63/100 (C)** — status: stable.

Positive: has types package; esm support; no vulnerabilities; has provenance; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 2.1.3 |
| Published | 2026-01-03 |
| First published | 2016-06-03 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/check-error) |
| Module format | ESM + CommonJS |
| Node | >= 16 |
| Dependencies | 0 |
| Unpacked size | 10.4 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 15 |
| Author | Jake Luer |
| Maintainers | chaijs |
| Keywords | check-error, error, chai util |

## Links

- npm: https://www.npmjs.com/package/check-error
- Repository: https://github.com/chaijs/check-error
- Homepage: https://github.com/chaijs/check-error#readme
- Issues: https://github.com/chaijs/check-error/issues
- npm.io page: https://npm.io/package/check-error

## Alternatives

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- [custom-error-generator](https://npm.io/package/custom-error-generator.md) — 2.0K weekly downloads
- [@technik-sde/prosemirror-recreate-transform](https://npm.io/package/@technik-sde/prosemirror-recreate-transform.md) — 1.5K weekly downloads
- [@suchipi/error-utils](https://npm.io/package/@suchipi/error-utils.md) — 78 weekly downloads

## Recent versions

- 2.1.3 (latest) — 2026-01-03
- 2.1.1 — 2024-05-08
- 2.1.0 — 2024-05-08
- 1.0.3 — 2023-09-27
- 2.0.0 — 2023-07-21
- 1.0.2 — 2016-06-27
- 1.0.1 — 2016-06-07
- 1.0.0 — 2016-06-03

## README

<h1 align=center>
  <a href="http://chaijs.com" title="Chai Documentation">
    <img alt="ChaiJS" src="http://chaijs.com/img/chai-logo.png">
  </a>
  <br>
  check-error
</h1>

<p align=center>
  Error comparison and information related utility for <a href="http://nodejs.org">node</a> and the browser.
</p>

## What is Check-Error?

Check-Error is a module which you can use to retrieve an Error's information such as its `message` or `constructor` name and also to check whether two Errors are compatible based on their messages, constructors or even instances.

## Installation

### Node.js

`check-error` is available on [npm](http://npmjs.org). To install it, type:

    $ npm install check-error

### Browsers

You can also use it within the browser; install via npm and use the `check-error.js` file found within the download. For example:

```html
<script src="./node_modules/check-error/check-error.js"></script>
```

## Usage

The primary export of `check-error` is an object which has the following methods:

* `compatibleInstance(err, errorLike)` - Checks if an error is compatible with another `errorLike` object. If `errorLike` is an error instance we do a strict comparison, otherwise we return `false` by default, because instances of objects can only be compatible if they're both error instances.
* `compatibleConstructor(err, errorLike)` - Checks if an error's constructor is compatible with another `errorLike` object. If `err` has the same constructor as `errorLike` or if `err` is an instance of `errorLike`.
* `compatibleMessage(err, errMatcher)` - Checks if an error message is compatible with an `errMatcher` RegExp or String (we check if the message contains the String).
* `getConstructorName(errorLike)` - Retrieves the name of a constructor, an error's constructor or `errorLike` itself if it's not an error instance or constructor.
* `getMessage(err)` - Retrieves the message of an error or `err` itself if it's a String. If `err` or `err.message` is undefined we return an empty String.

```js
import * as checkError 'check-error';
```

#### .compatibleInstance(err, errorLike)

```js
import * as checkError 'check-error';

const funcThatThrows = function() { throw new TypeError('I am a TypeError') };
let caughtErr;

try {
  funcThatThrows();
} catch(e) {
  caughtErr = e;
}

const sameInstance = caughtErr;

checkError.compatibleInstance(caughtErr, sameInstance); // true
checkError.compatibleInstance(caughtErr, new TypeError('Another error')); // false
```

#### .compatibleConstructor(err, errorLike)

```js
import * as checkError 'check-error';

const funcThatThrows = function() { throw new TypeError('I am a TypeError') };
let caughtErr;

try {
  funcThatThrows();
} catch(e) {
  caughtErr = e;
}

checkError.compatibleConstructor(caughtErr, Error); // true
checkError.compatibleConstructor(caughtErr, TypeError); // true
checkError.compatibleConstructor(caughtErr, RangeError); // false
```

#### .compatibleMessage(err, errMatcher)

```js
import * as checkError 'check-error';

const funcThatThrows = function() { throw new TypeError('I am a TypeError') };
let caughtErr;

try {
  funcThatThrows();
} catch(e) {
  caughtErr = e;
}

const sameInstance = caughtErr;

checkError.compatibleMessage(caughtErr, /TypeError$/); // true
checkError.compatibleMessage(caughtErr, 'I am a'); // true
checkError.compatibleMessage(caughtErr, /unicorn/); // false
checkError.compatibleMessage(caughtErr, 'I do not exist'); // false
```

#### .getConstructorName(errorLike)

```js
import * as checkError 'check-error';

const funcThatThrows = function() { throw new TypeError('I am a TypeError') };
let caughtErr;

try {
  funcThatThrows();
} catch(e) {
  caughtErr = e;
}

const sameInstance = caughtErr;

checkError.getConstructorName(caughtErr) // 'TypeError'
```

#### .getMessage(err)

```js
import * as checkError 'check-error';

const funcThatThrows = function() { throw new TypeError('I am a TypeError') };
let caughtErr;

try {
  funcThatThrows();
} catch(e) {
  caughtErr = e;
}

const sameInstance = caughtErr;

checkError.getMessage(caughtErr) // 'I am a TypeError'
```

---
_Source: https://npm.io/package/check-error · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._