import { createTimer, utils, onScroll } from 'animejs';

const [ $timer ] = utils.$('.timer');

createTimer({
  duration: 2000,
  alternate: true,
  loop: true,
  onUpdate: self => {
    $timer.innerHTML = self.iterationCurrentTime
  },
  autoplay: onScroll({
    target: $timer,
    container: '.scroll-container',
  })
});

<div class="scroll-container scroll-y">
  <div class="scroll-content grid square-grid">
    <div class="scroll-section padded">
      <div class="large centered row">
        <div class="label">scroll down</div>
      </div>
    </div>
    <div class="scroll-section padded">
      <div class="large centered row">
        <pre class="large log row">
          <span class="label">timer</span>
          <span class="timer value lcd">0</span>
        </pre>
      </div>
    </div>
  </div>
</div>