detectLanguage function

LanguageGuess? detectLanguage(String text)

Detects the dominant language of text; returns null when too short.

Heuristic, best-effort only: it compares the input's ranked trigrams against tiny built-in profiles using an out-of-place rank distance, so short or mixed text and unsupported languages can mis-detect. Returns null when fewer than _kMinTrigrams trigrams exist, since there is too little signal to decide.

Example:

detectLanguage('the quick brown fox and the lazy dog')?.language; // 'en'

Audited: 2026-06-12 11:26 EDT

Implementation

LanguageGuess? detectLanguage(String text) {
  final List<String> grams = languageTrigrams(text);
  if (grams.length < _kMinTrigrams) return null;
  // Score every profile and keep the smallest normalized distance. Using
  // firstOrNull-style folding avoids any bare .first on a possibly-empty list.
  LanguageGuess? best;
  for (final MapEntry<String, List<String>> entry in _kProfiles.entries) {
    final double score = _profileDistance(grams, entry.value);
    if (best == null || score < best.score) {
      best = LanguageGuess(entry.key, score);
    }
  }
  return best;
}