breakLongWords method

@useResult String breakLongWords(int charCount, String separator)

Inserts separator (e.g. soft hyphen) every charCount graphemes within long words.

Only inserts inside "words" (runs of non-whitespace). charCount must be positive. Uses character length, not grapheme; for grapheme-safe behavior use with ASCII or normalize. Returns the string with separators inserted in long words.

Throws ArgumentError if charCount is not positive.

Example:

'hello'.breakLongWords(2, '\u00ad');  // 'hel\u00adlo'

Implementation

@useResult
String breakLongWords(int charCount, String separator) {
  if (charCount < 1) {
    throw ArgumentError(_kErrCharCountPositive, _kParamCharCount);
  }
  if (isEmpty) return this;
  final List<String> wordsList = split(RegExp(r'\s+')).toList();
  if (wordsList.isEmpty) return this;
  final List<String> result = List<String>.filled(wordsList.length, '');
  final StringBuffer sb = StringBuffer();
  int idx = 0;
  for (final String word in wordsList) {
    if (word.length <= charCount) {
      result[idx++] = word;
    } else {
      sb.clear();
      for (int i = 0; i < word.length; i += charCount) {
        if (i > 0) sb.write(separator);
        final int end = (i + charCount).clamp(0, word.length);
        final int start = i.clamp(0, word.length);
        sb.write(word.substringSafe(start, end));
      }
      result[idx++] = sb.toString();
    }
  }
  return result.sublist(0, idx).join(' ');
}