React lazy load won't work inside React perfect scroll bar - reactjs

Question

I am using react-perfect-scrollbar to show images list.
Inside the perfect scroll bar, I am going to lazy load images. But it won't work.
import React, { useState, useCallback, useEffect } from 'react';
import PerfectScrollbar from 'react-perfect-scrollbar';
import useIsMountedRef from 'src/hooks/useIsMountedRef';
import LazyLoad from 'react-lazyload';
import {
Box,
Button,
Link,
List,
ListItem,
ListItemIcon,
ListItemText,
CircularProgress,
Typography,
makeStyles
} from '#material-ui/core';
const isMountedRef = useIsMountedRef();
const [images, setImages] = useState([]);
const getImages = useCallback(async () => {
try {
setLoading(true);
const response = await axios.get(`${backendUrl}/images/get/images`);
if (isMountedRef.current) {
setImages(response.data.projectImages);
}
} catch (err) {
console.error(err);
} finally {
if (isMountedRef.current) {
setLoading(false);
}
}
}, [isMountedRef]);
<PerfectScrollbar options={{ suppressScrollX: true }}>
<List className={classes.list}>
{images.map((image, i) => (
<ListItem
divider={i < images.length - 1}
key={i}
className={classes.listItem}
>
<ListItemIcon>
<LazyLoad height={90} key={i} overflow>
<img
src={`${awsS3Url}/${image.Key}`}
className={classes.listImage}
onClick={() => onSelect(`${awsS3Url}/${image.Key}`)}
/>
</LazyLoad>
</ListItemIcon>
<ListItemText
primary={GetFilename(image.Key)}
primaryTypographyProps={{ variant: 'h5' }}
secondary={bytesToSize(image.Size)}
className={classes.listItemText}
/>
<MoreButton
handleArchive={() => handleRemoveOne(image)}
/>
</ListItem>
))}
</List>
</PerfectScrollbar>
Some of images(the first view without scrolling) are showing.
When I scroll, the images won't load, only the list contents without images are showing.
What did I code wrong?

Answer 1

I had the same problem. The issue is that react-lazyload is trying to find a container that has its overflow property set to scroll or auto, but perfect-scrollbar sets its overflow property to hidden and handles the scrolling manually instead. So we have to tell react-lazyload manually which container it should monitor for scroll events.
This can, by documentation, be done in two ways; by passing an HTMLElement or a query selector string. Alas, there seems to be a bug in the library that causes the property to be ignored if it is not a string (https://github.com/twobin/react-lazyload/blob/055405125d0313014f0951cffc78345297f10a08/lib/index.js#L261) so currently the only way is to pass a query selector string.
But when I tried to pass a query selector string targeting the perfect-scrollbars container, it seems that the container might not always be there yet when react-lazyload attaches its event listeners, so we must check that the container is actually there before we initialize the LazyLoad-container.
So the relevant code is:
import React, { ReactElement, useRef, useState, useEffect } from 'react';
import PerfectScrollbar from 'react-perfect-scrollbar'
import LazyLoad from 'react-lazyload';
export default (): ReactElement => {
// Get a reference to the wrapper element so we know when it is created
const scrollbarWrapperRef = useRef(null);
// Initialize a state setter to notify the view when the scrollParent becomes available
const [scrollParent, setScrollParent] = useState<HTMLElement|null>(null);
// Adjust this selector to your liking
const scrollParentSelector = '#scrollbar-wrapper .scrollbar-container';
// Here we make sure that the PerfectScrollbar container is actually available before we let the content and the LazyLoads be created.
useEffect(() => {
const scrollParentElement = document.querySelector(scrollParentSelector);
if (scrollParentElement) {
setScrollParent(scrollParentElement);
}
}, [scrollbarWrapperRef.current]);
// The relevant DOM
return (
<div ref={scrollbarWrapperRef} id="scrollbar-wrapper">
<PerfectScrollbar>
{ scrollParent &&
<List>
{images.map((image, i) => (
<LazyLoad scrollContainer={scrollParentSelector}>
<img src="..." />
</LazyLoad>
))}
</List>
}
</PerfectScrollbar>
</div>
);
}