# isError
> Test if a value is an [Error][mdn-error] object.
## Usage
```javascript
var isError = require( '@stdlib/assert/is-error' );
```
#### isError( value )
Tests if a `value` is an [`Error`][mdn-error] object.
```javascript
var bool = isError( new Error( 'beep' ) );
// returns true
```
## Examples
```javascript
var isError = require( '@stdlib/assert/is-error' );
var bool = isError( new Error( 'error' ) );
// returns true
bool = isError( new EvalError( 'eval error' ) );
// returns true
bool = isError( new RangeError( 'range error' ) );
// returns true
bool = isError( new ReferenceError( 'reference error' ) );
// returns true
bool = isError( new SyntaxError( 'syntax error' ) );
// returns true
bool = isError( new TypeError( 'type error' ) );
// returns true
bool = isError( new URIError( 'URI error' ) );
// returns true
bool = isError( {} );
// returns false
bool = isError( null );
// returns false
```
[mdn-error]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error