app/javascript/flavours/glitch/components/scrollable_list.jsx
import PropTypes from 'prop-types';
import { Children, cloneElement, PureComponent } from 'react';
import classNames from 'classnames';
import { useLocation } from 'react-router-dom';
import { List as ImmutableList } from 'immutable';
import { connect } from 'react-redux';
import { supportsPassiveEvents } from 'detect-passive-events';
import { throttle } from 'lodash';
import ScrollContainer from 'flavours/glitch/containers/scroll_container';
import IntersectionObserverArticleContainer from '../containers/intersection_observer_article_container';
import { attachFullscreenListener, detachFullscreenListener, isFullscreen } from '../features/ui/util/fullscreen';
import IntersectionObserverWrapper from '../features/ui/util/intersection_observer_wrapper';
import { LoadMore } from './load_more';
import { LoadPending } from './load_pending';
import { LoadingIndicator } from './loading_indicator';
const MOUSE_IDLE_DELAY = 300;
const listenerOptions = supportsPassiveEvents ? { passive: true } : false;
/**
*
* @param {import('flavours/glitch/store').RootState} state
* @param {*} props
*/
const mapStateToProps = (state, { scrollKey }) => {
return {
preventScroll: scrollKey === state.dropdownMenu.scrollKey,
};
};
// This component only exists to be able to call useLocation()
const IOArticleContainerWrapper = ({id, index, listLength, intersectionObserverWrapper, trackScroll, scrollKey, children}) => {
const location = useLocation();
return (<IntersectionObserverArticleContainer
id={id}
index={index}
listLength={listLength}
intersectionObserverWrapper={intersectionObserverWrapper}
saveHeightKey={trackScroll ? `${location.key}:${scrollKey}` : null}
>
{children}
</IntersectionObserverArticleContainer>);
};
IOArticleContainerWrapper.propTypes = {
id: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
index: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
listLength: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
scrollKey: PropTypes.string.isRequired,
intersectionObserverWrapper: PropTypes.object.isRequired,
trackScroll: PropTypes.bool.isRequired,
children: PropTypes.node,
};
class ScrollableList extends PureComponent {
static propTypes = {
scrollKey: PropTypes.string.isRequired,
onLoadMore: PropTypes.func,
onLoadPending: PropTypes.func,
onScrollToTop: PropTypes.func,
onScroll: PropTypes.func,
trackScroll: PropTypes.bool,
isLoading: PropTypes.bool,
showLoading: PropTypes.bool,
hasMore: PropTypes.bool,
numPending: PropTypes.number,
prepend: PropTypes.node,
append: PropTypes.node,
alwaysPrepend: PropTypes.bool,
emptyMessage: PropTypes.node,
children: PropTypes.node,
bindToDocument: PropTypes.bool,
preventScroll: PropTypes.bool,
};
static defaultProps = {
trackScroll: true,
};
state = {
fullscreen: null,
cachedMediaWidth: 300,
};
intersectionObserverWrapper = new IntersectionObserverWrapper();
handleScroll = throttle(() => {
if (this.node) {
const scrollTop = this.getScrollTop();
const scrollHeight = this.getScrollHeight();
const clientHeight = this.getClientHeight();
const offset = scrollHeight - scrollTop - clientHeight;
if (scrollTop > 0 && offset < 400 && this.props.onLoadMore && this.props.hasMore && !this.props.isLoading) {
this.props.onLoadMore();
}
if (scrollTop < 100 && this.props.onScrollToTop) {
this.props.onScrollToTop();
} else if (this.props.onScroll) {
this.props.onScroll();
}
if (!this.lastScrollWasSynthetic) {
// If the last scroll wasn't caused by setScrollTop(), assume it was
// intentional and cancel any pending scroll reset on mouse idle
this.scrollToTopOnMouseIdle = false;
}
this.lastScrollWasSynthetic = false;
}
}, 150, {
trailing: true,
});
mouseIdleTimer = null;
mouseMovedRecently = false;
lastScrollWasSynthetic = false;
scrollToTopOnMouseIdle = false;
_getScrollingElement = () => {
if (this.props.bindToDocument) {
return (document.scrollingElement || document.body);
} else {
return this.node;
}
};
setScrollTop = newScrollTop => {
if (this.getScrollTop() !== newScrollTop) {
this.lastScrollWasSynthetic = true;
this._getScrollingElement().scrollTop = newScrollTop;
}
};
clearMouseIdleTimer = () => {
if (this.mouseIdleTimer === null) {
return;
}
clearTimeout(this.mouseIdleTimer);
this.mouseIdleTimer = null;
};
handleMouseMove = throttle(() => {
// As long as the mouse keeps moving, clear and restart the idle timer.
this.clearMouseIdleTimer();
this.mouseIdleTimer = setTimeout(this.handleMouseIdle, MOUSE_IDLE_DELAY);
if (!this.mouseMovedRecently && this.getScrollTop() === 0) {
// Only set if we just started moving and are scrolled to the top.
this.scrollToTopOnMouseIdle = true;
}
// Save setting this flag for last, so we can do the comparison above.
this.mouseMovedRecently = true;
}, MOUSE_IDLE_DELAY / 2);
handleWheel = throttle(() => {
this.scrollToTopOnMouseIdle = false;
}, 150, {
trailing: true,
});
handleMouseIdle = () => {
if (this.scrollToTopOnMouseIdle && !this.props.preventScroll) {
this.setScrollTop(0);
}
this.mouseMovedRecently = false;
this.scrollToTopOnMouseIdle = false;
};
componentDidMount () {
this.attachScrollListener();
this.attachIntersectionObserver();
attachFullscreenListener(this.onFullScreenChange);
// Handle initial scroll position
this.handleScroll();
}
getScrollPosition = () => {
if (this.node && (this.getScrollTop() > 0 || this.mouseMovedRecently)) {
return { height: this.getScrollHeight(), top: this.getScrollTop() };
} else {
return null;
}
};
getScrollTop = () => {
return this._getScrollingElement().scrollTop;
};
getScrollHeight = () => {
return this._getScrollingElement().scrollHeight;
};
getClientHeight = () => {
return this._getScrollingElement().clientHeight;
};
updateScrollBottom = (snapshot) => {
const newScrollTop = this.getScrollHeight() - snapshot;
this.setScrollTop(newScrollTop);
};
getSnapshotBeforeUpdate (prevProps) {
const someItemInserted = Children.count(prevProps.children) > 0 &&
Children.count(prevProps.children) < Children.count(this.props.children) &&
this.getFirstChildKey(prevProps) !== this.getFirstChildKey(this.props);
const pendingChanged = (prevProps.numPending > 0) !== (this.props.numPending > 0);
if (pendingChanged || someItemInserted && (this.getScrollTop() > 0 || this.mouseMovedRecently || this.props.preventScroll)) {
return this.getScrollHeight() - this.getScrollTop();
} else {
return null;
}
}
componentDidUpdate (prevProps, prevState, snapshot) {
// Reset the scroll position when a new child comes in in order not to
// jerk the scrollbar around if you're already scrolled down the page.
if (snapshot !== null) {
this.updateScrollBottom(snapshot);
}
}
cacheMediaWidth = (width) => {
if (width && this.state.cachedMediaWidth !== width) {
this.setState({ cachedMediaWidth: width });
}
};
componentWillUnmount () {
this.clearMouseIdleTimer();
this.detachScrollListener();
this.detachIntersectionObserver();
detachFullscreenListener(this.onFullScreenChange);
}
onFullScreenChange = () => {
this.setState({ fullscreen: isFullscreen() });
};
attachIntersectionObserver () {
let nodeOptions = {
root: this.node,
rootMargin: '300% 0px',
};
this.intersectionObserverWrapper
.connect(this.props.bindToDocument ? {} : nodeOptions);
}
detachIntersectionObserver () {
this.intersectionObserverWrapper.disconnect();
}
attachScrollListener () {
if (this.props.bindToDocument) {
document.addEventListener('scroll', this.handleScroll);
document.addEventListener('wheel', this.handleWheel, listenerOptions);
} else {
this.node.addEventListener('scroll', this.handleScroll);
this.node.addEventListener('wheel', this.handleWheel, listenerOptions);
}
}
detachScrollListener () {
if (this.props.bindToDocument) {
document.removeEventListener('scroll', this.handleScroll);
document.removeEventListener('wheel', this.handleWheel, listenerOptions);
} else {
this.node.removeEventListener('scroll', this.handleScroll);
this.node.removeEventListener('wheel', this.handleWheel, listenerOptions);
}
}
getFirstChildKey (props) {
const { children } = props;
let firstChild = children;
if (children instanceof ImmutableList) {
firstChild = children.get(0);
} else if (Array.isArray(children)) {
firstChild = children[0];
}
return firstChild && firstChild.key;
}
setRef = (c) => {
this.node = c;
};
handleLoadMore = e => {
e.preventDefault();
this.props.onLoadMore();
};
handleLoadPending = e => {
e.preventDefault();
this.props.onLoadPending();
// Prevent the weird scroll-jumping behavior, as we explicitly don't want to
// scroll to top, and we know the scroll height is going to change
this.scrollToTopOnMouseIdle = false;
this.lastScrollWasSynthetic = false;
this.clearMouseIdleTimer();
this.mouseIdleTimer = setTimeout(this.handleMouseIdle, MOUSE_IDLE_DELAY);
this.mouseMovedRecently = true;
};
render () {
const { children, scrollKey, trackScroll, showLoading, isLoading, hasMore, numPending, prepend, alwaysPrepend, append, emptyMessage, onLoadMore } = this.props;
const { fullscreen } = this.state;
const childrenCount = Children.count(children);
const loadMore = (hasMore && onLoadMore) ? <LoadMore visible={!isLoading} onClick={this.handleLoadMore} /> : null;
const loadPending = (numPending > 0) ? <LoadPending count={numPending} onClick={this.handleLoadPending} /> : null;
let scrollableArea = null;
if (showLoading) {
scrollableArea = (
<div className='scrollable scrollable--flex' ref={this.setRef}>
<div role='feed' className='item-list'>
{prepend}
</div>
<div className='scrollable__append'>
<LoadingIndicator />
</div>
</div>
);
} else if (isLoading || childrenCount > 0 || hasMore || !emptyMessage) {
scrollableArea = (
<div className={classNames('scrollable', { fullscreen })} ref={this.setRef} onMouseMove={this.handleMouseMove}>
<div role='feed' className='item-list'>
{prepend}
{loadPending}
{Children.map(this.props.children, (child, index) => (
<IOArticleContainerWrapper
key={child.key}
id={child.key}
index={index}
listLength={childrenCount}
intersectionObserverWrapper={this.intersectionObserverWrapper}
trackScroll={trackScroll}
scrollKey={scrollKey}
>
{cloneElement(child, {
getScrollPosition: this.getScrollPosition,
updateScrollBottom: this.updateScrollBottom,
cachedMediaWidth: this.state.cachedMediaWidth,
cacheMediaWidth: this.cacheMediaWidth,
})}
</IOArticleContainerWrapper>
))}
{loadMore}
{!hasMore && append}
</div>
</div>
);
} else {
scrollableArea = (
<div className={classNames('scrollable scrollable--flex', { fullscreen })} ref={this.setRef}>
{alwaysPrepend && prepend}
<div className='empty-column-indicator'>
{emptyMessage}
</div>
</div>
);
}
if (trackScroll) {
return (
<ScrollContainer scrollKey={scrollKey}>
{scrollableArea}
</ScrollContainer>
);
} else {
return scrollableArea;
}
}
}
export default connect(mapStateToProps, null, null, { forwardRef: true })(ScrollableList);