What could be wrong if the code works?

Question

JavaScript

The code works, but the teacher says there is an error. I do not see her.

class Carousel {

  constructor(s) {
    let initConfig = (obj) => {
      const settings = {
        containerID: '#carousel',
        interval: 5000,
        slideID: '.slide',
      };

      if (obj !== undefined) {
        settings.containerID = obj.containerID || '#carousel';
        settings.interval = obj.interval || 5000;
        settings.slideID = obj.slideID || '.slide';
      }

      return settings;
    };

    let settings = initConfig(s);


    this.container = document.querySelector(settings.containerID);
    this.slides = this.container.querySelectorAll(settings.slideID);


    this.interval = settings.interval;
  }

  _initProps() {
    this.slidesCount = this.slides.length;
    this.currentSlide = 0;
    this.isPlaying = true;

    this.SPACE = ' ';
    this.LEFT_ARROW = 'ArrowLeft';
    this.RIGHT_ARROW = 'ArrowRight';
    this.FA_PAUSE = '<i class="far fa-pause-circle"></i>';
    this.FA_PLAY = '<i class="far fa-play-circle"></i>';
    this.FA_PREV = '<i class="fas fa-angle-left"></i>';
    this.FA_NEXT = '<i class="fas fa-angle-right"></i>';
  }

  _initControls() {
    let controls = document.createElement('div');
    const PAUSE = `<span id="pause-btn" class="control-pause">${this.FA_PAUSE}</span>`;
    const PREV = `<span id="prev-btn" class="control-prev">${this.FA_PREV}</span>`;
    const NEXT = `<span id="next-btn" class="control-next">${this.FA_NEXT}</span>`;

    controls.setAttribute('class', 'controls');
    controls.setAttribute('id', 'controls-container');
    controls.innerHTML = PAUSE + PREV + NEXT;

    this.container.appendChild(controls);

    this.pauseBtn = this.container.querySelector('#pause-btn');
    this.prevBtn = this.container.querySelector('#prev-btn');
    this.nextBtn = this.container.querySelector('#next-btn');
  }

  _initIndicators() {
    let indicators = document.createElement('div');
    indicators.setAttribute('class', 'indicators');
    indicators.setAttribute('id', 'indicators-container');


    for (let i = 0; i < this.slidesCount; i++) {
      let indicator = document.createElement('div');
      indicator.setAttribute('class', 'indicator');
      //indicator.setAttribute('data-slide-to', `${i}`);
      i === 0 && indicator.classList.add('active');
      indicator.dataset.slideTo = `${i}`;
      indicators.appendChild(indicator);
    }

    this.container.appendChild(indicators);

    this.indContainer = this.container.querySelector('#indicators-container');
    this.indItems = this.indContainer.querySelectorAll('.indicator');
  }

  _initListeners() {
    this.pauseBtn.addEventListener('click', this.pausePlay.bind(this));
    this.prevBtn.addEventListener('click', this.prev.bind(this));
    this.nextBtn.addEventListener('click', this.next.bind(this));
    this.indContainer.addEventListener('click', this.indicate.bind(this));
    document.addEventListener('keydown', this._pressKey.bind(this));
  }

  _gotoNth(n) {
    this.slides[this.currentSlide].classList.toggle('active');
    this.indItems[this.currentSlide].classList.toggle('active');
    this.currentSlide = (this.slidesCount + n) % this.slidesCount;
    this.slides[this.currentSlide].classList.toggle('active');
    this.indItems[this.currentSlide].classList.toggle('active');
  }

  _gotoPrev() {
    this._gotoNth(this.currentSlide - 1);
  }

  _gotoNext() {
    this._gotoNth(this.currentSlide + 1);
  }

  _play() {
    this.pauseBtn.innerHTML = this.FA_PAUSE;
    this.isPlaying = !this.isPlaying;
    this.timerID = setInterval(this._gotoNext.bind(this), this.interval);
  }

  _pause() {
    if (this.isPlaying) {
      this.pauseBtn.innerHTML = this.FA_PLAY;
      this.isPlaying = !this.isPlaying;
      clearInterval(this.timerID);
    }
  }

  indicate(e) {
    let target = e.target;

    if (target.classList.contains('indicator')) {
      this._pause();
      this._gotoNth(+target.getAttribute('data-slide-to'));
    }
  }

  _pressKey(e) {
    if (e.key === this.SPACE) this.pausePlay();
    if (e.key === this.RIGHT_ARROW) this.next();
    if (e.key === this.LEFT_ARROW) this.prev();
  }

  pausePlay() {
    if (this.isPlaying) this._pause();
    else this._play();
  }

  prev() {
    this._pause();
    this._gotoPrev();
  }

  next() {
    this._pause();
    this._gotoNext();
  }


  init() {
    //this.indContainer.style.display = 'flex';
    //document.querySelector('.controls').style.display = 'block';
    this._initProps();
    this._initControls();
    this._initIndicators();
    this._initListeners();
    this.timerID = setInterval(() => this._gotoNext(), this.interval);
  }
}

class SwipeCarousel extends Carousel {
  _initListeners() {
    super._initListeners();
    this.container.addEventListener('touchstart', this._swipeStart.bind(this));
    this.container.addEventListener('touchend', this._swipeEnd.bind(this));
  }

  _swipeStart(e) {
    this.swipeStartX = e.changedTouches[0].pageX;
  }

  _swipeEnd(e) {
    this.swipeEndX = e.changedTouches[0].pageX;
    if (this.swipeStartX - this.swipeEndX > 100) this.next();
    if (this.swipeStartX - this.swipeEndX < -100) this.prev();
  }
}