event_loop.dart

import 'dart:async';

/*
* @description: event loop
*
* @author: jixiaoyong
* @email: jixiaoyong1995@gmail.com
* @date: 6/9/2022
*/
main() {
  scheduleMicroTaskFunc();
  futureFunc();
  timerFunc();
}

void scheduleMicroTaskFunc() {
  scheduleMicrotask(() {
    print("Hello, I am microtask");
  });

  Future.microtask(
      () => print("Hello, I am microtask created by Future.microtask"));
}

void futureFunc() async {
  Future.delayed(const Duration(seconds: 1), () {
    print("Hello, I am future");
  });

  Future.value(1).then((value) {
    print("Hello, I am future created by Future.value");
  });

  Future.sync(() => print("Hello, I am future created by Future.sync"));

  Future.forEach(
      [1, 2, 3],
      (element) =>
          print("Hello, I am future($element) created by Future.forEach"));

  Future.error(Exception("Hello, I am future created by Future.error"))
      .onError((error, stackTrace) => print(error));

  Future.any([
    Future(() {
      return "I am Future run immediately Future.any";
    }),
    Future.delayed(const Duration(seconds: 1), () {
      return "I am Future run delay, will be discard Future.any";
    })
  ]).then((value) => print(value));

  Future.wait([
    Future(() {
      return "I am Future run immediately Future.wait 1/2";
    }),
    Future.delayed(const Duration(seconds: 1), () {
      return "I am Future run delay Future.wait 2/2";
    })
  ]).then((value) => print(value));

  var repeatCounter = 0;
  Future.doWhile(() async {
    if (repeatCounter++ < 3) {
      print("repeat ($repeatCounter/3) inner Future.doWhile");
      await Future.delayed(const Duration(seconds: 1));
      return true;
    }
    return false;
  });
}

void timerFunc() {
  Timer.periodic(const Duration(seconds: 1), (timer) {
    print("Hello, I am running inner(${timer.tick}/2) Timer.periodic");
    if (timer.tick == 2) {
      timer.cancel();
    }
  });

  Timer.run(() {
    print(
        "Hello, I will run asynchronously as soon as possible with Timer.run");
  });
}

/// result:
/*
Hello, I am future created by Future.sync
Hello, I am future(1) created by Future.forEach
Hello, I am future(2) created by Future.forEach
Hello, I am future(3) created by Future.forEach
repeat (1/3) inner Future.doWhile
Hello, I am microtask
Hello, I am microtask created by Future.microtask
Hello, I am future created by Future.value
Exception: Hello, I am future created by Future.error
I am Future run immediately Future.any
Hello, I will run asynchronously as soon as possible with Timer.run
Hello, I am future
[I am Future run immediately Future.wait 1/2, I am Future run delay Future.wait 2/2]
repeat (2/3) inner Future.doWhile
Hello, I am running inner(1/2) Timer.periodic
Hello, I am running inner(2/2) Timer.periodic
repeat (3/3) inner Future.doWhile
*/