Хочу вернуть число, возвращает [object Object]

class ProgressBar {
  constructor() {
    this.input = $('.progress-bar').find('.progress-bar__input');
  }

  progress(percentage) {
    let val = 0;
    if (percentage > 100) {
      val = 100;
    } else if (percentage < 0) {
      val = 0;
    } else {
      val = percentage;
    }
    $('.progress-bar__fill').css('width', `${100 - val}%`);
    $('.progress-bar__percent').text(`${val}%`);
  }

  onChange() {
    this.input.change(function() {
      console.log(typeof + this.value);
      return this.value;
    });
    console.log(this.input.change());
    this.progress(this.input.change());
  }
}

const progressBar = new ProgressBar();

progressBar.onChange();

.progress-bar {
  background-image: linear-gradient(90deg, rgb(255, 76, 76) 0%, rgb(238, 185, 0) 44%, rgb(62, 179, 84) 100%);
  position: relative;
  overflow: hidden;
  max-width: 540px;
  width: 100%;
  height: 54px;
  margin-right: 20px;
  border: 1px solid;
  border-radius: 6px;
}

.progress-bar__fill {
  position: absolute;
  right: 0;
  top: 0;
  height: 100%;
  width: 100%;
  background-color: #eaeaea;
  transition: all .3s;
}

.progress-bar__percent {
  position: absolute;
  top: 10px;
  right: 20px;
  font-size: 18px;
  line-height: 32px;
  font-weight: 600;
  color: #fff;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="progress-bar">
  <label>
    <input data-percentage="99" type="hidden" class="progress-bar__input">
  </label>
  <span class="progress-bar__fill"></span>
  <span class="progress-bar__percent"></span>
</div>