lerp method

Implementation

FlyFontWeightToken lerp(FlyFontWeightToken other, double t) {
  final result = <String, FontWeight>{};
  final allKeys = {..._allValues.keys, ...other._allValues.keys};

  for (final key in allKeys) {
    final valueA = _allValues[key];
    final valueB = other._allValues[key];
    if (valueA != null && valueB != null) {
      final weightA = valueA.index;
      final weightB = valueB.index;
      final interpolatedIndex = (weightA + (weightB - weightA) * t).round();
      result[key] = FontWeight
          .values[interpolatedIndex.clamp(0, FontWeight.values.length - 1)];
    } else if (valueA != null) {
      result[key] = valueA;
    } else if (valueB != null) {
      result[key] = valueB;
    }
  }

  return FlyFontWeightToken(
    thin: result['thin']!,
    extralight: result['extralight']!,
    light: result['light']!,
    normal: result['normal']!,
    medium: result['medium']!,
    semibold: result['semibold']!,
    bold: result['bold']!,
    extrabold: result['extrabold']!,
    black: result['black']!,
    extras: Map.fromEntries(
      result.entries.where(
        (e) => ![
          'thin',
          'extralight',
          'light',
          'normal',
          'medium',
          'semibold',
          'bold',
          'extrabold',
          'black',
        ].contains(e.key),
      ),
    ),
  );
}