enum_map 0.4.0-2.dev

A Map with compile-time check that every enum constant has an entry in it.

A Map with the compile-time check that every enum constant has an entry in it.

Overview

For an enum like this

enum Fruit { apple, orange, banana }

... you can generate the following class:

class FruitMap<V> extends EnumMap<Fruit, V> { // implements Map<Fruit, V>
  FruitMap({
    required this.apple,
    required this.orange,
    required this.banana,
  });
  // ...
}

Which means that the app will only build if you set all the values in the constructor. And then you can treat this object like an ordinary map.

Usage

@MakeMap()
@MakeUnmodifiableMap()
enum Fruit { apple, orange, banana }

void main() {
  final modifiableMap = FruitMap<String>(apple: 'a', orange: 'o', banana: 'b');
  print(modifiableMap);  // prints: {Fruit.apple: a, Fruit.orange: o, Fruit.banana: b}
  print(modifiableMap[Fruit.apple]);      // prints: a
  print(modifiableMap.get(Fruit.apple));  // prints: a

  const unmodifiableMap = UnmodifiableFruitMap<String>(apple: 'a', orange: 'o', banana: 'b');
  print(unmodifiableMap);  // prints: {Fruit.apple: a, Fruit.orange: o, Fruit.banana: b}
  print(unmodifiableMap[Fruit.apple]);      // prints: a
  print(unmodifiableMap.get(Fruit.apple));  // prints: a
}

The generated classes contain:

• All 21 of the public members of the Map interface.
• V get(Fruit key) -- the non-nullable getter that guarantees the result of type V.
• toString() that works like with the default maps.

Migrating from the Pre-Macro Version

1. Change the annotations:
   • Replace @enumMap with @MakeMap().
   • Replace @unmodifiableEnumMap with @MakeUnmodifiableMap().
2. Delete all *.g.dart files.
3. Delete enum_map_gen package from your pubspec.yaml. Run dart pub get.
4. Check if you still need build_runner package for other packages. If you don't, delete it and run dart pub get.
5. Otherwise, regenerate all *.g.dart files that exist for reasons other than this package.

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