Dart enum to and from string

enum.dart

//Copyright (C) 2012 Sergey Akopkokhyants. All Rights Reserved.
//Author: akserg

/// Emulation of Java Enum class.
///
/// Example:
///
/// class Meter<int> extends Enum<int> {
///
///  const Meter(int val) : super (val);
///
///  static const Meter HIGH = const Meter(100);
///  static const Meter MIDDLE = const Meter(50);
///  static const Meter LOW = const Meter(10);
/// }
///
/// and usage:
///
/// assert (Meter.HIGH, 100);
/// assert (Meter.HIGH is Meter);

abstract class Enum<T> {
  final T _value;

  const Enum(this._value);

  T get value => _value;
}

enum_utils.dart

import 'enum.dart';

class EnumUtils {
  /// EnumUtils.nameToString(Sizes.big) // 'big'
  /// EnumUtils.nameToString(null, () => '-') // '-'
  static String toNameString<T>(T enumValue, {String Function() orElse}) {
    if (enumValue is Enum<String>) {
      return enumValue.value;
    }

    var str = enumValue?.toString() ?? (orElse != null ? orElse() : null);
    if (str?.contains('.') ?? false) return str?.split('.')?.last;
    return str;
  }

  /// EnumUtils.fromName(Sizes.values, 'big')
  /// EnumUtils.fromName(Sizes.values, 'small', or: Sizes.small)
  /// EnumUtils.fromName(Sizes.values, 'medium', orElse: (name, values) => values.first())
  static T fromNameString<T>(List<T> enumValues, String name, {T Function(String name, List<T> values) orElse, T or}) {
    return enumValues.firstWhere((enumItem) {
      return enumItem.toString()?.split('.')?.last == name;
    }, orElse: () =>
      orElse != null
        ? orElse(name, enumValues)
        : or
    );
  }
}