rest_parse_hex_color()

rest_parse_hex_color( string $color ): string|false

function rest_parse_hex_color( $color ) {
	$regex = '|^#([A-Fa-f0-9]{3}){1,2}$|';
	if ( ! preg_match( $regex, $color, $matches ) ) {
		return false;
	}

	return $color;
}