# hasUTF16SurrogatePairAt
> Test if a position in a string marks the start of a [UTF-16][utf-16] surrogate pair.
## Usage
```javascript
var hasUTF16SurrogatePairAt = require( '@stdlib/assert/has-utf16-surrogate-pair-at' );
```
#### hasUTF16SurrogatePairAt( string, position )
Tests if a `position` (in [UTF-16][utf-16] code units) in a `string` marks the start of a [UTF-16][utf-16] surrogate pair.
```javascript
var bool = hasUTF16SurrogatePairAt( '🌷', 0 );
// returns true
bool = hasUTF16SurrogatePairAt( '🌷', 1 );
// returns false
```
## Notes
- Note that `position` does **not** refer to a visual character position, but to an index in the ordered sequence of [UTF-16][utf-16] code units.
## Examples
```javascript
var hasUTF16SurrogatePairAt = require( '@stdlib/assert/has-utf16-surrogate-pair-at' );
var bool = hasUTF16SurrogatePairAt( '🌷', 0 );
// returns true
bool = hasUTF16SurrogatePairAt( '🌷', 1 );
// returns false
```
* * *
## CLI
### Usage
```text
Usage: has-utf16-surrogate-pair-at [options] [] --pos=
Options:
-h, --help Print this message.
-V, --version Print the package version.
--pos index Position in string.
```
### Examples
```bash
$ has-utf16-surrogate-pair-at --pos=0 🌷
true
```
To use as a [standard stream][standard-streams],
```bash
$ echo -n '🌷' | has-utf16-surrogate-pair-at --pos=1
false
```
[utf-16]: https://en.wikipedia.org/wiki/UTF-16
[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams