syllableCounter property Null safety

Implementation

@override
SyllableCounter get syllableCounter => (term) {
      term = term.trim();
      // return 0 if term is empty
      if (term.isEmpty) return 0;
      // return 1 if term length is less than 3
      if (term.length < 3) {
        return 1;
      } else {
        // initialize the return value
        var count = 0;
        // split term into terms at non-word characters
        final terms =
            term.split(RegExp(Porter2StemmerConstants.rEnglishNonWordChars));
        for (var e in terms) {
          // stem the remaining term with the SyllableStemmer.
          // DO NOT USE the analyzer stemmer as it may be overridden and we
          // must make sure the trailing silent e's are removed and vowel "y"s
          // are converted to "i"
          e = SyllableStemmer().stem(e);
          // count apostropied syllables like "d'Azure" and remove the
          // apostrophied prefix
          e = e.replaceAllMapped(RegExp(r"(?<=\b)([a-zA-Z]')"), (match) {
            count++;
            return '';
          });
          // check for terms with capitals or remaining punctuation
          if (e.toUpperCase() == e) {
            // this is more than likely an acronym, so add 1
            count++;
          } else {
            // add all the single vowels, diphtongs and triptongs.
            // As e has been stemmed by the Porter2 stemmer, we know trailing
            // silent e's have been removed and vowel "y"s converted to "i"
            e = e.toLowerCase();
            if (e.contains(RegExp(r"[^aeiou\s\-\']+(?=\b)"))) {
              // term ends in one or more consonants or ys
              count += RegExp(r'[aeiouyà-æè-ðò-öø-ÿ]+').allMatches(e).length;
              // check for stemmed words ending in 3 or more consonants
              count +=
                  e.contains(RegExp(r"[^aeiouyà-æè-ðò-öø-ÿ\s\-\']{3,}(?=\b)"))
                      ? 1
                      : 0;
            } else {
              count += RegExp(r'[aeiouyà-æè-ðò-öø-ÿ]+').allMatches(e).length;
            }
          }
        }
        // if count is 0, return 1 because a word must have at least one syllable
        return count < 1 ? 1 : count;
      }
    };