Promise Sequence

promiseSequence.js

class Task {
  constructor({ id, thunk }) {
    this.id = id;
    this.thunk = thunk;
    this._done = false;
  }

  setDone() {
    this._done = true;
  }
}

class Sequence {
  constructor(tasks) {
    this._tasks = tasks;
  }

  _stillExist(task) {
    const index = this._tasks.findIndex(i => i.id === task.id);
    
    return index > -1;
  }

  async run() {
    const arr = [...this._tasks];
    for (let task of arr) {
      if (!this._stillExist(task)) {
        continue;
      }
      try {
        const res = await task.thunk();
        task.setDone();
        console.log(res);
      } catch (err) {
        console.log(err);
      }
    }
  }
  
  removeById(id) {
    const index = this._tasks.findIndex(i => i.id === id);
    if (index > -1) {
      this._tasks.splice(index, 1);
    } else {
      console.warn(`Task with id ${id} doesn't exists`);
    }
  }
}

const createThunk = (index) => () => new Promise((res) => {
    setTimeout(() => {
      res(index);
    }, 100);
  });

// just generates some array with tasks
// each task should have unique id and thunk - function which returns a promise
const pArray = [...Array(10).keys()].map((index) => {
  return new Task({ id: index, thunk: createThunk(index) })
});

const sequence = new Sequence(pArray);

// you can run it
sequence.run()
  .then(() => console.log('done'));

// pass an id to remove
sequence.removeById(5);