MultiToken<T extends Object> class

A token representing multiple values of T for dependency injection.

const usPresidents = const MultiToken<String>('usPresidents');

@Component(
  selector: 'presidents-list',
  providers: const [
    const ValueProvider.forToken(usPresidents, 'George Washington'),
    const ValueProvider.forToken(usPresidents, 'Abraham Lincoln'),
  ],
)
class PresidentsListComponent {
  // Will be ['George Washington', 'Abraham Lincoln'].
  final List<String> items;

  PresidentsListComponent(@Inject(usPresidents) this.items);
}

The type T is not required, but is recommended, otherwise it is dynamic.

The only positional argument, uniqueName, is used to determine uniqueness of the token. That is, const MultiToken('SECRETS') is identical to const MultiToken('SECRETS') in another library or package.

You may also sub-class MultiToken to create a "more unique" token:

class UsPresidents extends MultiToken<String> {
  const UsPresidents();
}

const usPresidents = const UsPresidents();

@Component(
  selector: 'presidents-list',
  providers: const [
    const ValueProvider.forToken(usPresidents, 'George Washington'),
    const ValueProvider.forToken(usPresidents, 'Abraham Lincoln'),
  ],
)
class PresidentsListComponent {
  // Will be ['George Washington', 'Abraham Lincoln'].
  final List<String> items;

  PresidentsListComponent(@Inject(usPresidents) this.items);
}

NOTE: The List<T> returned by dependency injection is not guaranteed to be identical across invocations - that is, a new List instance is created every time a provider backed by a MultiToken is used:

const usPresidents = MultiToken<String>('usPresidents');

void example(Injector i) {
  final a = i.provideToken(usPresidents);
  final b = i.provideToken(usPresidents);
  print(identical(a, b)); // false
}

WARNING: It is not supported to create a non-const instance of this class or sub-types of this class. Instances should only be created or referenced using the const operator.

Inheritance
Annotations
  • @optionalTypeArgs

Constructors

MultiToken([String uniqueName = ''])
const

Properties

hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
override

Operators

operator ==(Object other) → bool
The equality operator.
inherited