enumerator_annotation 0.0.1-dev.2

Code generation utilities for Dart enums

Enumerator

Code generation utilities for Dart enums

enumerator_builder is a lightweight Dart code generator that adds useful, type-safe helpers to enums—such as predicate getters derived from enum values, lookup utilities, functional mapping, and custom field lookups, using a single annotation.

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Features

With one annotation, enumerator generates:

• Predicate boolean getters derived from enum value names (for example, is<EnumValue>)
• Safe lookup helpers (fromName, fromNameOrNull)
• Functional mapping (map, mapOrNull)
• Membership checks (isIn)
• Custom lookup fields (e.g. API values)
• Configurable per enum and globally

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Installation

Add the dependencies:

• Dart

dart pub add \
  enumerator_annotation \
  dev:build_runner \
  dev:enumerator_builder

• Flutter

flutter pub add \
  enumerator_annotation \
  dev:build_runner \
  dev:enumerator_builder

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Basic Usage

1. Annotate your enum

// status.dart

import 'package:enumerator_annotation/enumerator_annotation.dart';

part 'status.enum.dart';

@enumerator
enum Status { pending, success, error }

Run the generator:

dart run build_runner build
# or
dart run build_runner watch

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2. Use the generated helpers

void main() {
  const status = Status.pending;

  // Predicate getters derived from enum value names
  print(status.isPending); // true
  print(status.isSuccess); // false
  print(status.isError);   // false

  // Lookup by name
  Status enum1 = Status.values.fromName('pending');
  Status? enum2 = Status.values.fromNameOrNull('something');

  // Functional mapping
  int value1 = status.map(
    pending: () => 1,
    success: () => 2,
    error: () => 3,
  );

  // Optional mapping
  String? value2 = status.mapOrNull(
    success: () => 'Success',
    // error: () { ... },
  );

  // Membership check
  status.isIn({.pending, .error}); // true
}

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Custom Lookup Fields

Enums often need to map to API or external values. enumerator supports this using @enumLookup.

@enumerator
enum Role {
  admin('ROLE-ADMIN'),
  user('ROLE-USER'),
  guest('ROLE-GUEST');

  const Role(this.apiValue);

  @enumLookup
  final String apiValue;
}

Generated usage:

final role = Role.values.fromApiValue('ROLE-ADMIN');
print(role); // Role.admin

Role.values.fromApiValueOrNull('UNKNOWN'); // null

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Configuration

All features are enabled by default.

Configuration can be applied per enum or globally.

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Per-enum configuration

@Enumerator(
  predicate: true,
  iterableLookup: true,
  map: true,
  isIn: true,
)
enum Status { pending, success, error }

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Global configuration (build.yaml)

targets:
  $default:
    builders:
      enumerator_builder:
        options:
          predicate: false
          iterableLookup: false
          map: false
          isIn: false

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Configuration options

Option	Description	Default
predicate	Generates predicate getters derived from enum values (eg. isPending)	true
iterableLookup	Generates fromName, fromNameOrNull helpers	true
map	Generates map, mapOrNull	true
isIn	Generates isIn()	true

Resolution priority:

1. Enum annotation
2. build.yaml
3. Default value (true)

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Contributing

Issues, feature ideas, and pull requests are welcome.

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License

MIT