Dart – Emulating enums using Constant Constructor

Yan Cui

I help clients go faster for less using serverless technologies.

Whilst Dart doesn’t have support for enum types but it turns out you can do a pretty good job of emulating it using Dart’s constant constructors (which allows you to create compile-time constants with your class, which in .Net you’re restricted to numbers, booleans, strings and null).

Using the technique from this SO answer you will start with a base class for your enum types:

	abstract class Enum<T> {
	final T value;

	const Enum(this.value);
	}

view raw enum.dart hosted with

by GitHub

From here, you can create other specialized enum types, such as:

	import 'enum.dart';

	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);
	}

view raw meter.dart hosted with

by GitHub

Thank you, mr Sergy Akopkokhyants for this elegant little solution.

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Dart – Emulating enums using Constant Constructor

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