@function __trunc(
  $string,
  $options: null,
  $guard: null,
  $omission: null,
  $length: null,
  $separator: null
) {
  @if ($guard and __is-iteratee-call($string, $options, $guard)) {
    $options: null;
  }

  $length: __either($length, __const("DEFAULT_TRUNC_LENGTH"));
  $omission: __either($omission, __const("DEFAULT_TRUNC_OMISSION"));
  $separator: __either($separator, null);

  @if $options != null {
    @if (__is-map($options)) {
      $separator: if(
        map-has-key($options, "separator"),
        __get($options, "separator"),
        $separator
      );
      $length: if(
        map-has-key($options, "length"),
        __get($options, "length"),
        $length
      );
      $omission: if(
        map-has-key($options, "omission"),
        __base-to-string(__get($options, "omission")),
        $omission
      );
    } @else {
      $length: __parse-int($options);
    }
  }

  $string: __base-to-string($string);

  @if ($length >= str-length($string)) {
    @return $string;
  }

  $end: $length - str-length($omission);

  @if ($end < 1) {
    @return $omission;
  }

  $result: str-slice($string, 0, $end);

  @if ($separator == null) {
    @return $result + $omission;
  }

  @if (__string-index-of($string, $separator, $end) != $end) {
    $index: __string-last-index-of($result, $separator);

    @if ($index > -1) {
      $result: str-slice($result, 0, $index - 1);
    }
  }

  @return $result + $omission;
}

/// Truncates `$string` if it is longer than the given maximum string length.
/// The last characters of the truncated string are replaced with the omission
/// string which defaults to "...".
///
///
/// @access public
/// @group String
/// @param {string} $string [''] - The string to truncate.
/// @param {Map|number} $options [null] - The options object or maximum string length.
/// @param {number} $length [30] - The maximum string length.
/// @param {string} $omission ['...'] - The string to indicate text is omitted.
/// @param {string} $separator [null] - The separator pattern to truncate to.
/// @returns {string} Returns the truncated string.
/// @example scss
/// $foo: _trunc('hi-diddly-ho there, neighborino');
/// // => 'hi-diddly-ho there, neighbo...'
///
/// $foo: _trunc('hi-diddly-ho there, neighborino', 24);
/// // => 'hi-diddly-ho there, n...'
///
/// $foo: _trunc('hi-diddly-ho there, neighborino',
///   $length: 24,
///   $separator: ' '
/// );
/// // => 'hi-diddly-ho there,...'
///
/// $foo: _trunc('hi-diddly-ho there, neighborino',
///   $omission: ' (...)'
/// );
/// // => 'hi-diddly-ho there, neig (...)'

@function _trunc(
  $string,
  $options: null,
  $guard: null,
  $omission: null,
  $length: null,
  $separator: null
) {
  @return call(
    get-function("__trunc"),
    $string,
    $options,
    $guard,
    $omission,
    $length,
    $separator
  );
}