# isWhitespace
> Test whether a string contains only [white space][whitespace] characters.
## Usage
```javascript
var isWhitespace = require( '@stdlib/assert/is-whitespace' );
```
#### isWhitespace( value )
Tests whether a string contains only [white space][whitespace] characters.
```javascript
var bool = isWhitespace( ' ' );
// returns true
```
## Notes
- A [white space][whitespace] character is defined as one of the 25 characters defined as a [white space][whitespace] ("WSpace=Y","WS") character in the Unicode 9.0 character database, as well as one related [white space][whitespace] character without the Unicode character property "WSpace=Y" (zero width non-breaking space which was deprecated as of Unicode 3.2).
- For non-string values, the function returns `false`.
## Examples
```javascript
var isWhitespace = require( '@stdlib/assert/is-whitespace' );
var out = isWhitespace( ' ' );
// returns true
out = isWhitespace( '' );
// returns false
out = isWhitespace( '\\r\\n' );
// returns false
out = isWhitespace( 123 );
// returns false
```
[whitespace]: https://en.wikipedia.org/wiki/Whitespace_character