import { Circle, Infinite } from 'infinite-circle';

// defined action which cause running read and write operation
let visibilityCircle = new Circle({
    listen: notify => {
        window.addEventListener('scroll', notify);
        window.addEventListener('resize', notify);
    },
    unlisten: notify => {
        window.removeEventListener('scroll', notify);
        window.removeEventListener('resize', notify);
    }
});

// defined read and write operation
const img1 = document.querySelector('.img1');
let img1CircleId = visibilityCircle.register({
    read: () => {
        let rect = img1.getBoundingClientRect();

        return intersectionPercentage(rect);
    },
    write({ payload }) => {
        if (payload > 0) {
            loadImage(img1);
            visibilityCircle.unregister(img1CircleId);
        }
    }
});
// register more elements

// register circle to synchronising infinite loop
let infinite = new Infinite();
infinite.add(visibilityCircle);

// other functions
function intersectionPercentage(rect) {
    .
    .
    .
    return percent;
}

function loadImage(imageElement) {
    .
    .
    .
}