module_scope › Classes › ModuleScope<T extends dynamic>

ModuleScope<T extends dynamic>

class ModuleScope<T extends dynamic>

Widget that manages the lifecycle of a Module and exposes its DI container.

ModuleScope creates a ModuleController, initializes the module, and provides the resulting Binder to descendants via ModuleProvider. It handles loading and error states and supports configurable retention policies that control when the controller is disposed or reused.

Basic Usage

ModuleScope<AuthModule>(
  module: AuthModule(),
  child: const AuthPage(),
)

Retention Policy

Controls how the ModuleController is retained across widget rebuilds:

• ModuleRetentionPolicy.strict -- controller disposed on every unmount.
• ModuleRetentionPolicy.routeBound -- controller disposed when route pops.
• ModuleRetentionPolicy.keepAlive -- controller cached in ModuleRetainer, survives widget unmount, disposed on route termination or explicit eviction.

Retention Key vs Override Scope

Important distinction:

• retentionKey determines cache identity for KeepAlive policy.
• overrideScope affects DI bindings but NOT cache identity.

Two scopes with the same retentionKey but different overrideScopes will share the same cached controller (first scope's overrides win).

To make overrides affect caching, include scope identity in the key:

ModuleScope(
  module: MyModule(),
  retentionPolicy: ModuleRetentionPolicy.keepAlive,
  retentionKey: 'my-module-${identityHashCode(overrideScope)}',
  overrideScope: overrideScope,
  child: ...,
)

See also:

• ModuleProvider for accessing the module's Binder from descendants.
• ModularityRoot for top-level DI configuration.

Constructors

ModuleScope() const

const ModuleScope({dynamic key, required T module, required dynamic child, dynamic args, dynamic loadingBuilder, (dynamic Function(dynamic, Object? error, dynamic retry))? errorBuilder, dynamic retentionPolicy = ModuleRetentionPolicy.routeBound, Object? retentionKey, Map<String, Object?>? retentionExtras, (void Function(dynamic))? overrides, dynamic overrideScope})

Create a ModuleScope that manages the lifecycle of module.

Implementation

const ModuleScope({
  super.key,
  required this.module,
  required this.child,
  this.args,
  this.loadingBuilder,
  this.errorBuilder,
  this.retentionPolicy = ModuleRetentionPolicy.routeBound,
  this.retentionKey,
  this.retentionExtras,
  this.overrides,
  this.overrideScope,
});

Properties

args final

final dynamic args

Arguments passed to Configurable.configure if module implements it.

Typed as dynamic because ModuleScope only has one type parameter T (the module type). The actual args type is enforced by the Configurable mixin at the module level — Configurable<A>.configure(A args) provides compile-time safety where it matters. Adding a second type parameter here would degrade ergonomics for the common case (non-configurable modules).

Implementation

final dynamic args;

child final

final dynamic child

Widget subtree that can access the module's DI container.

Implementation

final Widget child;

errorBuilder final

final (dynamic Function(dynamic, Object? error, dynamic retry))? errorBuilder

Builder for error state UI with retry callback.

Implementation

final Widget Function(BuildContext, Object? error, VoidCallback retry)?
errorBuilder;

hashCode no setter inherited

int get hashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Inherited from Object.

Implementation

external int get hashCode;

loadingBuilder final

final dynamic loadingBuilder

Builder for loading state UI.

Implementation

final WidgetBuilder? loadingBuilder;

module final

final T module

The module instance to manage.

Implementation

final T module;

overrides final

final (void Function(dynamic))? overrides

Overrides applied to module's bindings.

Implementation

final void Function(Binder)? overrides;

overrideScope final

final dynamic overrideScope

Override scope tree for this module and its imports.

Note: Does NOT affect retentionKey derivation. See class documentation.

Implementation

final ModuleOverrideScope? overrideScope;

retentionExtras final

final Map<String, Object?>? retentionExtras

Additional data for retention key derivation.

Implementation

final Map<String, Object?>? retentionExtras;

retentionKey final

final Object? retentionKey

Explicit key for KeepAlive cache identity.

If null, derived from module type, route, and arguments. Does NOT include overrideScope by default.

Implementation

final Object? retentionKey;

retentionPolicy final

final dynamic retentionPolicy

How the controller lifecycle is managed.

Defaults to ModuleRetentionPolicy.routeBound.

Implementation

final ModuleRetentionPolicy retentionPolicy;

runtimeType no setter inherited

Type get runtimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

external Type get runtimeType;

Methods

createState()

dynamic createState()

Implementation

@override
State<ModuleScope<T>> createState() => _ModuleScopeState<T>();

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Object.

Implementation

external String toString();

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Object.

Implementation

external bool operator ==(Object other);