UseEffect class

A ReactterHook that manages side-effect.

The side-effect logic into the callback function is executed when dependencies of ReactterState argument has changes or instance trigger LifeCycle.didMount event:

UseEffect(
  () {
    print("Executed by state changed or 'didMount' event");
  },
  [state],
);

The callback function can return a cleanup function to manage the effect cleanup. The cleanup function is executed before the dependencies of ReactterState argument has changes or instance trigger LifeCycle.willUnmount event:

UseEffect(
  () {
    print("Executed by state changed or 'didMount' event");

    return () {
      print("Executed before state changed or 'willUnmount' event");
    };
  },
  [state],
);

RECOMMENDED: Use it on class constructor:

class AppController {
  final state = UseState(0);

  AppController() {
    UseEffect(
      () {
        print("Executed by state changed or 'didMount' event");

        return () {
          print("Executed before state changed or 'willUnmount' event");
        };
      },
      [state],
    );

    Timer.periodic(Duration(seconds: 1), (_) => state.value++);
  }
}

If you want to execute the effect on initialization, you can use UseEffect.runOnInit:

UseEffect.runOnInit(
  () {
    print("Executed on initialization and 'didMount' event");
  },
  [],
);

You can also use the DispatchEffect mixin to execute the effect on initialization:

class AppController with DispatchEffect {
  AppController() {
    UseEffect(
      () {
        print("Executed on initialization and 'didMount' event");
      },
      [],
    );
  }
}

Use bind method to bind the instance, if you want to execute the effect within the instance context:

UseEffect(
  () {
    print("Executed by `didMount` event of 'useController' instance");
  },
  [],
).bind(useController);

NOTE: A UseEffect instance can only be binded to one instance at a time. When create a new instance of UseEffect on the instance that is created by instance manager, this instance will be binded to it automatically.

NOTE: The UseEffect instance will be disposed automatically when the instance binded is destroyed by instance manager.

If the UseEffect instance didn't have an instance binded or the instance binded is not created by instance manager, you must dispose it manually, using the dispose method:

final useEffect = UseEffect(
  () {
    print("Executed by state changed");
  },
  [state],
);

[...]

useEffect.dispose();

See also:

Inheritance

Constructors

UseEffect(Function callback, List<ReactterState> dependencies)
A ReactterHook that manages side-effect.
UseEffect.runOnInit(Function callback, List<ReactterState> dependencies)
A ReactterHook that manages side-effect.

Properties

$ → HookRegister
This variable is used to register Hook and attach the StateBase that are defined here.
final
callback → Function
Function to control side-effect and effect cleanup.
final
dependencies → List<ReactterState>
It's used to store the states as dependencies of UseEffect.
final
eventManager → EventManager
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
instanceBinded → Object?
The reference instance to the current state.
no setterinherited
instanceManager → InstanceManager
no setterinherited
isDisposed → bool
Returns true if the state has been disposed.
no setterinherited
logger → Logger
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
stateManager → StateManager<StateBase>
no setterinherited

Methods

bind(Object instance) → void
Stores a reference to an object instance
dispose() → void
Called when this object is removed
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
refresh() → void
It's used to notify listeners that the state has been updated. It is typically called after making changes to the state object.
inherited
toString() → String
A string representation of this object.
inherited
unbind() → void
Removes the reference to the object instance
update([covariant Function? callback]) → void
Executes callback, and notifies the listeners about the update.
inherited

Operators

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