# isNegativeZero > Test if a value is a number equal to negative zero.
## Usage ```javascript var isNegativeZero = require( '@stdlib/assert/is-negative-zero' ); ``` #### isNegativeZero( value ) Tests if a `value` is a `number` having a value equal to negative zero. ```javascript var Number = require( '@stdlib/number/ctor' ); var bool = isNegativeZero( -0.0 ); // returns true bool = isNegativeZero( new Number( -0.0 ) ); // returns true bool = isNegativeZero( -3.14 ); // returns false bool = isNegativeZero( 0.0 ); // returns false bool = isNegativeZero( null ); // returns false ``` #### isNegativeZero.isPrimitive( value ) Tests if a `value` is a primitive `number` equal to negative zero. ```javascript var Number = require( '@stdlib/number/ctor' ); var bool = isNegativeZero.isPrimitive( -0.0 ); // returns true bool = isNegativeZero.isPrimitive( new Number( -0.0 ) ); // returns false ``` #### isNegativeZero.isObject( value ) Tests if a `value` is a `Number` object having a value equal to negative zero. ```javascript var Number = require( '@stdlib/number/ctor' ); var bool = isNegativeZero.isObject( -0.0 ); // returns false bool = isNegativeZero.isObject( new Number( -0.0 ) ); // returns true ```
## Examples ```javascript var Number = require( '@stdlib/number/ctor' ); var isNegativeZero = require( '@stdlib/assert/is-negative-zero' ); var bool = isNegativeZero( -0.0 ); // returns true bool = isNegativeZero( new Number( -0.0 ) ); // returns true bool = isNegativeZero( -3.14 ); // returns false bool = isNegativeZero( 0.0 ); // returns false bool = isNegativeZero( 5.0 ); // returns false bool = isNegativeZero( '-0' ); // returns false bool = isNegativeZero( null ); // returns false ```