If you use Waypointsjs with Ionic 4, you can try a configuration similar to this:
const homeContent = document.querySelector('.homeContent')
const innerScroll = homeContent.shadowRoot.querySelector('.inner-scroll')
const element = homeContent.querySelector('.my-element')
const waypoint = new Waypoint({
context: innerScroll,
offset: '30%',
element: element,
handler: function (direction) {
console.log('on scrolling', direction, this.element)
}
})
It works very well, check my website => https://proyecto26.com/
Regards, Nicholls