How to use the ember-in-viewport/utils/check-scroll-direction function in ember-in-viewport

_triggerDidScrollDirection(contextEl = null, sensitivity = 1) {
    assert('You must pass a valid context element to _triggerDidScrollDirection', contextEl);
    assert('sensitivity cannot be 0', sensitivity);

    const elementId = get(this, 'elementId');
    const lastDirectionForEl = lastDirection[elementId];
    const lastPositionForEl = lastPosition[elementId];
    const newPosition = {
      top: contextEl.scrollTop,
      left: contextEl.scrollLeft
    };

    const scrollDirection = checkScrollDirection(lastPositionForEl, newPosition, sensitivity);
    const directionChanged = scrollDirection !== lastDirectionForEl;

    if (scrollDirection && directionChanged && get(this, 'viewportDidScroll')) {
      this.trigger('didScroll', scrollDirection);
      lastDirection[elementId] = scrollDirection;
    }

    lastPosition[elementId] = newPosition;
  },