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import React, { PureComponent } from 'react';
import { ScrollContainer } from 'react-router-scroll-4';
import PropTypes from 'prop-types';
import IntersectionObserverArticleContainer from 'flavours/glitch/containers/intersection_observer_article_container';
import LoadMore from './load_more';
import IntersectionObserverWrapper from 'flavours/glitch/util/intersection_observer_wrapper';
import { throttle } from 'lodash';
import { List as ImmutableList } from 'immutable';
import classNames from 'classnames';
import { attachFullscreenListener, detachFullscreenListener, isFullscreen } from 'flavours/glitch/util/fullscreen';
import LoadingIndicator from './loading_indicator';
export default class ScrollableList extends PureComponent {
static contextTypes = {
router: PropTypes.object,
};
static propTypes = {
scrollKey: PropTypes.string.isRequired,
onLoadMore: PropTypes.func,
onScrollToTop: PropTypes.func,
onScroll: PropTypes.func,
trackScroll: PropTypes.bool,
shouldUpdateScroll: PropTypes.func,
isLoading: PropTypes.bool,
showLoading: PropTypes.bool,
hasMore: PropTypes.bool,
prepend: PropTypes.node,
alwaysPrepend: PropTypes.bool,
emptyMessage: PropTypes.node,
children: PropTypes.node,
};
static defaultProps = {
trackScroll: true,
};
state = {
fullscreen: null,
};
intersectionObserverWrapper = new IntersectionObserverWrapper();
handleScroll = throttle(() => {
if (this.node) {
const { scrollTop, scrollHeight, clientHeight } = this.node;
const offset = scrollHeight - scrollTop - clientHeight;
if (400 > offset && this.props.onLoadMore && !this.props.isLoading) {
this.props.onLoadMore();
}
if (scrollTop < 100 && this.props.onScrollToTop) {
this.props.onScrollToTop();
} else if (this.props.onScroll) {
this.props.onScroll();
}
}
}, 150, {
trailing: true,
});
componentDidMount () {
this.attachScrollListener();
this.attachIntersectionObserver();
attachFullscreenListener(this.onFullScreenChange);
// Handle initial scroll posiiton
this.handleScroll();
}
getScrollPosition = () => {
if (this.node && this.node.scrollTop > 0) {
return {height: this.node.scrollHeight, top: this.node.scrollTop};
} else {
return null;
}
}
updateScrollBottom = (snapshot) => {
const newScrollTop = this.node.scrollHeight - snapshot;
if (this.node.scrollTop !== newScrollTop) {
this.node.scrollTop = newScrollTop;
}
}
getSnapshotBeforeUpdate (prevProps, prevState) {
const someItemInserted = React.Children.count(prevProps.children) > 0 &&
React.Children.count(prevProps.children) < React.Children.count(this.props.children) &&
this.getFirstChildKey(prevProps) !== this.getFirstChildKey(this.props);
if (someItemInserted && this.node.scrollTop > 0) {
return this.node.scrollHeight - this.node.scrollTop;
} 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);
}
componentWillUnmount () {
this.detachScrollListener();
this.detachIntersectionObserver();
detachFullscreenListener(this.onFullScreenChange);
}
onFullScreenChange = () => {
this.setState({ fullscreen: isFullscreen() });
}
attachIntersectionObserver () {
this.intersectionObserverWrapper.connect({
root: this.node,
rootMargin: '300% 0px',
});
}
detachIntersectionObserver () {
this.intersectionObserverWrapper.disconnect();
}
attachScrollListener () {
this.node.addEventListener('scroll', this.handleScroll);
}
detachScrollListener () {
this.node.removeEventListener('scroll', this.handleScroll);
}
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();
}
defaultShouldUpdateScroll = (prevRouterProps, { location }) => {
if ((((prevRouterProps || {}).location || {}).state || {}).mastodonModalOpen) return false;
return !(location.state && location.state.mastodonModalOpen);
}
render () {
const { children, scrollKey, trackScroll, shouldUpdateScroll, showLoading, isLoading, hasMore, prepend, alwaysPrepend, emptyMessage, onLoadMore } = this.props;
const { fullscreen } = this.state;
const childrenCount = React.Children.count(children);
const loadMore = (hasMore && childrenCount > 0 && onLoadMore) ? <LoadMore visible={!isLoading} onClick={this.handleLoadMore} /> : 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 || !emptyMessage) {
scrollableArea = (
<div className={classNames('scrollable', { fullscreen })} ref={this.setRef}>
<div role='feed' className='item-list'>
{prepend}
{React.Children.map(this.props.children, (child, index) => (
<IntersectionObserverArticleContainer
key={child.key}
id={child.key}
index={index}
listLength={childrenCount}
intersectionObserverWrapper={this.intersectionObserverWrapper}
saveHeightKey={trackScroll ? `${this.context.router.route.location.key}:${scrollKey}` : null}
>
{React.cloneElement(child, {getScrollPosition: this.getScrollPosition, updateScrollBottom: this.updateScrollBottom})}
</IntersectionObserverArticleContainer>
))}
{loadMore}
</div>
</div>
);
} else {
scrollableArea = (
<div className={classNames('scrollable', { fullscreen })} ref={this.setRef} style={{ flex: '1 1 auto', display: 'flex', flexDirection: 'column' }}>
{alwaysPrepend && prepend}
<div className='empty-column-indicator'>
{emptyMessage}
</div>
</div>
);
}
if (trackScroll) {
return (
<ScrollContainer scrollKey={scrollKey} shouldUpdateScroll={shouldUpdateScroll || this.defaultShouldUpdateScroll}>
{scrollableArea}
</ScrollContainer>
);
} else {
return scrollableArea;
}
}
}
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