Dark 事件循环测试

//dark 事件循环
void main() {
  // test0();
  // test1();
  // future3();
  // future4();
  // future5();
  // future6();
  // feture7();
  //  feture8();
  feture9();
}

void feture9() { // 9->8->0->2->1->3->4->6->7->5  ( Future(() =>print('5')); 最后加入队列）
  Future x = Future(() => null);
  x.then((value){
    print('0');
    scheduleMicrotask(() => print('1'));
  }).then((value)=>print('2'));

  Future x1= Future(() => print('3'));
  x1.then((value){
    print('4');
    Future(() =>print('5'));
  }).then((value) => print('6'));

  Future(() => print("7"));
  scheduleMicrotask(() {
    print('8');
  });

  print('9');
}


void feture8() { // 6->5->1->3->2->4  ( then((value)=>print('8')); 是先放入微任务中)
  Future x = Future(() => null);
  x.then((value){
    print('1');
    scheduleMicrotask(() => print('2'));
  }).then((value)=>print('3'));

  Future(() => print("4"));
  scheduleMicrotask(() {
    print('5');
  });

  print('6');
}

void feture7() { // 5->3->1->4->2
  Future x = Future(() => print("1"));
  Future(() => print("2"));
  scheduleMicrotask(() {
    print('3');
  });
  x.then((value) => print('4'));
  print('5');
}

void future6() {
  //beging -> end -> micotask->A /A over ->B /B over
  print('beging');
  Future(() => print("A")).then((value) => print("A over"));
  Future(() => print("B")).then((value) => print("B over"));

  scheduleMicrotask(() {
    //priority height
    print("micotask");
  });

  print('end');
}

void future5() {
  //quque  finish => print  (task 1->task 2->task 3)
  Future.wait([
    Future(() {
      return "task 1";
    }),
    Future(() {
      return "task 2";
    }),
    Future(() {
      return "task 3";
    }),
  ]).then((value) => print(value[0] + value[1] + value[2]));
}

void future4() {
  // queue  依赖 (task1 over-> task1 task2 over -> task1 task2 task3 over)
  Future(() {
    return "task1";
  }).then((value) {
    print("$value over");
    return '$value task2';
  }).then((value) {
    print("$value over");
    return '$value task3';
  }).then((value) {
    print("$value over");
    return '$value task4';
  });
}

void future3() async {
  // queue 安照顺序执行 (task 1->task 2->task 3->task 4)
  Future(() {
    return "task 1";
  }).then((value) => print('$value'));

  Future(() {
    sleep(Duration(seconds: 1));
    return "task 2";
  }).then((value) => print('$value'));

  Future(() {
    return "task 3";
  }).then((value) => print('$value'));

  Future(() {
    return "task 4";
  }).then((value) => print('$value'));
}

void test1() {
  future1();
  print('A'); // B->A->C->D
}

void future1() {
  Future(() {
    sleep(Duration(seconds: 1));
    print('C');
  }).then((value) => print('D'));

  print('B');
}

void test2() {
  future2();
  print('A'); //A->C->D-> B
}

void future2() async {
  // 整个函数都变成异步
  await Future(() {
    sleep(Duration(seconds: 1));
    print('C');
  }).then((value) => print('D'));

  print('B');
}

void test0() {
  future0();
  print('做其他事情');
}

future0() async {
  print('开始data=$_data');
  //耗时操作
  Future future = Future(() {
    for (int i = 0; i < 1000000000; i++) {}
    return '网络数据';
  });

  future.then((value) => print('结果data=$value'));
  print('再干点事情!');
}