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# hasUTF16SurrogatePairAt

> Test if a position in a string marks the start of a [UTF-16][utf-16] surrogate pair.

<section class="usage">

## 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
```

</section>

<!-- /.usage -->

<section class="notes">

## 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.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var hasUTF16SurrogatePairAt = require( '@stdlib/assert/has-utf16-surrogate-pair-at' );

var bool = hasUTF16SurrogatePairAt( '🌷', 0 );
// returns true

bool = hasUTF16SurrogatePairAt( '🌷', 1 );
// returns false

```

</section>

<!-- /.examples -->

* * *

<section class="cli">

## CLI

<section class="usage">

### Usage

```text
Usage: has-utf16-surrogate-pair-at [options] [<string>] --pos=<index>

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
         --pos index           Position in string.
```

</section>

<!-- /.usage -->

<section class="examples">

### 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
```

</section>

<!-- /.examples -->

</section>

<!-- /.cli -->

<section class="links">

[utf-16]: https://en.wikipedia.org/wiki/UTF-16

[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams

</section>

<!-- /.links -->