import { createDraggable, utils } from 'animejs';

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

let snaps = 0;

createDraggable('.square', {
  container: '.grid',
  snap: 16,
  modifier: utils.snap(16), // also snap the element while draggin
  onSnap: () => $value.textContent = ++snaps
});

<div class="large padded grid square-grid">
  <pre class="large log row">
    <span class="label">snaps</span>
    <span class="value">0</span>
  </pre>
  <div class="square draggable"></div>
</div>