A parameter metadata that marks a dependency as optional.

Injector provides null if the dependency is not found.

Example

class Engine {}

@Injectable()
class Car {
  final Engine engine;
  constructor(@Optional() this.engine);
}

var injector = Injector.resolveAndCreate([Car]);
expect(injector.get(Car).engine, isNull);

Constructors

Optional()
const

Properties

hashCode → int
The hash code for this object. [...]
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
inherited
toString() → String
Returns a string representation of this object.
inherited

Operators

operator ==(other) → bool
The equality operator. [...]
inherited