RxJS CurrentThreadScheduler の動きに近い何か

currentthreadscheduler.js

// RxJS CurrentThreadScheduler
const queue = [];
const enqueue = (action) => queue.push(action);
const peek = () => queue[0];
const dequeue = () => queue.shift();
const run = () => {
  while (queue.length > 0) {
    const action = peek();
    action();
    dequeue();
  }
};
const schedule = (action) => {
  if (queue.length > 0) {
    enqueue(action);
  } else {
    enqueue(action);
    run();
  }
};

schedule(() => console.log('aiueo'));

schedule(() => {
  console.log('1');
  schedule(() => {
    console.log('2')
  });
  schedule(() => {
    console.log('3');
    schedule(() => {
      console.log('3-1');
    });
  });
  schedule(() => {
    console.log('4');
  })
});
// aiueo
// 1
// 2
// 3
// 4
// 3-1