gg_once_per_cycle 1.3.5

Use GgOncePerCycle to trigger tasks multiple times while ensuring they are only executed one time during a run loop cycle.

Trigger tasks multiple times, but execute them only one time per run loop cycle

Use GgOncePerCycle to trigger tasks multiple times while ensuring they are only executed one time during a run loop cycle.

Usage

A simple usage example:

import 'package:gg_once_per_cycle/gg_once_per_cycle.dart';

void main() async {
  // Create a task
  var counter = 0;
  task() => print('Task ${++counter}');

  // Give the task to a OncePerCycle instance
  final oncePerCycle = GgOncePerCycle(task: task);

  // Trigger the task multiple times
  oncePerCycle.trigger();
  oncePerCycle.trigger();
  oncePerCycle.trigger();

  // Wait for the next cycle
  await Future.delayed(Duration(microseconds: 1));

  // The task has only called one time
  assert(counter == 1);

  // Now we are in the next cycle and trigger the task again
  oncePerCycle.trigger();
  oncePerCycle.trigger();

  await Future.delayed(Duration(microseconds: 1));

  // And again the task has called only one other time
  assert(counter == 2);

  // Output:
  // Task 1
  // Task 2

  // Finally dispose the trigger to prevent that things
  // are executed lately.
  oncePerCycle.dispose();
  oncePerCycle.trigger();

  // Output:
  // No output, because previous dispose

  // ..................................................................
  // Assume a test where you want to control the execution by yourself
  var counterBefore = counter;
  final oncePerCycleTest = GgOncePerCycle(task: task, isTest: true);

  // Trigger
  oncePerCycleTest.trigger();
  await Future.delayed(Duration(microseconds: 1));

  // Nothing has happened, because isTest is true.
  assert(counter == counterBefore);

  // Trigger execution manually
  oncePerCycleTest.executeNow();

  // Now the task is executed
  assert(counter == counterBefore + 1);

  // ..................................................
  // Use Future.microtask instead of scheduleMicrotask
  counterBefore = counter;
  final ownScheduleMethodTest = GgOncePerCycle(
    task: task,
    scheduleTask: Future.microtask,
  );

  // Trigger
  ownScheduleMethodTest.trigger();
  await Future.delayed(Duration(microseconds: 1));

  // Now the task is executed
  assert(counter == counterBefore + 1);
}

Features and bugs

Please file feature requests and bugs at GitHub.