hasUTF16SurrogatePairAt

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

Usage

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

hasUTF16SurrogatePairAt( string, position )

Tests if a position (in UTF-16 code units) in a string marks the start of a UTF-16 surrogate pair.

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 code units.

Examples

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

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

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

CLI

Usage

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.

Examples

$ has-utf16-surrogate-pair-at --pos=0 🌷
true

To use as a standard stream,

$ echo -n '🌷' | has-utf16-surrogate-pair-at --pos=1
false