https://github.com/netsells/dominion
Utilities for implementing domain-driven design in Dart.
https://github.com/netsells/dominion
Last synced: about 1 month ago
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Utilities for implementing domain-driven design in Dart.
- Host: GitHub
- URL: https://github.com/netsells/dominion
- Owner: netsells
- License: mit
- Created: 2020-11-25T08:14:12.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2021-03-06T21:01:28.000Z (about 4 years ago)
- Last Synced: 2025-03-04T09:04:01.203Z (2 months ago)
- Language: Dart
- Size: 6.84 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# Dominion
Dominion is a small set of utilities for implementing domain-driven design in Dart.
## Usage
### Value objects
In DDD, a value object represents an object that is not uniquely identifiable, but may require validation (e.g. a password).
You can implement value objects with Dominion, by extending the `ValueObject` abstract class:
```dart
class PasswordFailure {
final String message;
const PasswordFailure(this.message);
}
class Password extends ValueObject {
final Either value;
factory Password(String input) {
assert(input != null);
// Validate the input
if (input.isEmpty) {
// Input is empty; return Left
return Password._(left(PasswordFailure('Password is empty.')));
} else if (input.length < 8) {
// Input is too short; return Left
return Password._(
left(
PasswordFailure('Password must be at least 8 characters.'),
),
);
} else {
// Input is valid; return Right
return Password._(right(input));
}
}
const Password._(this.value);
}
```
The `ValueObject` class includes a few helpful methods and getters, including:
- `value`, which returns either the value or the failure, depending on the validation result.
- This field is an instance of `Either`, which is provided by the [dartz](https://pub.dev/packages/dartz) package (included with Dominion)
- `getOrCrash`, which returns the value or throws `UnexpectedValueException` if it's invalid
- `getOrElse`, which returns the value, or the given default if the value is invalid
- `isValid`, which returns `true` if the value is valid and `false` otherwise
### Entities
An entity represents a business object which should be uniquely identifiable; in other words, entities are objects with IDs.
You can use the `Entity` abstract class to enforce this requirement on a class. Do this by implementing `Entity`.
```dart
// Users are Entities whose IDs are integers
class User implements Entity {
final int id; // This field is an int because we are implementing Entity
final String email;
const User(this.id, this.email);
}
```