Generalized the infinite scrollable list (#4697)
abcang
7 years ago
committed by
Eugen Rochko
parent
938cd2875b
commit
0827c09c44
@ -0,0 +1,122 @@
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import React from 'react';
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import PropTypes from 'prop-types';
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import ImmutablePureComponent from 'react-immutable-pure-component';
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import scheduleIdleTask from '../features/ui/util/schedule_idle_task';
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import getRectFromEntry from '../features/ui/util/get_rect_from_entry';
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export default class IntersectionObserverArticle extends ImmutablePureComponent {
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static propTypes = {
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intersectionObserverWrapper: PropTypes.object,
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id: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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index: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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listLength: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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children: PropTypes.node,
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};
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state = {
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isHidden: false, // set to true in requestIdleCallback to trigger un-render
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}
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shouldComponentUpdate (nextProps, nextState) {
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if (!nextState.isIntersecting && nextState.isHidden) {
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// It's only if we're not intersecting (i.e. offscreen) and isHidden is true
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// that either "isIntersecting" or "isHidden" matter, and then they're
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// the only things that matter (and updated ARIA attributes).
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return this.state.isIntersecting || !this.state.isHidden || nextProps.listLength !== this.props.listLength;
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} else if (nextState.isIntersecting && !this.state.isIntersecting) {
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// If we're going from a non-intersecting state to an intersecting state,
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// (i.e. offscreen to onscreen), then we definitely need to re-render
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return true;
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}
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// Otherwise, diff based on "updateOnProps" and "updateOnStates"
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return super.shouldComponentUpdate(nextProps, nextState);
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}
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componentDidMount () {
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if (!this.props.intersectionObserverWrapper) {
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// TODO: enable IntersectionObserver optimization for notification statuses.
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// These are managed in notifications/index.js rather than status_list.js
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return;
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}
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this.props.intersectionObserverWrapper.observe(
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this.props.id,
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this.node,
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this.handleIntersection
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);
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this.componentMounted = true;
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}
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componentWillUnmount () {
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if (this.props.intersectionObserverWrapper) {
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this.props.intersectionObserverWrapper.unobserve(this.props.id, this.node);
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}
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this.componentMounted = false;
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}
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handleIntersection = (entry) => {
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if (this.node && this.node.children.length !== 0) {
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// save the height of the fully-rendered element
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this.height = getRectFromEntry(entry).height;
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if (this.props.onHeightChange) {
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this.props.onHeightChange(this.props.status, this.height);
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}
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}
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this.setState((prevState) => {
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if (prevState.isIntersecting && !entry.isIntersecting) {
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scheduleIdleTask(this.hideIfNotIntersecting);
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}
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return {
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isIntersecting: entry.isIntersecting,
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isHidden: false,
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};
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});
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}
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hideIfNotIntersecting = () => {
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if (!this.componentMounted) {
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return;
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}
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// When the browser gets a chance, test if we're still not intersecting,
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// and if so, set our isHidden to true to trigger an unrender. The point of
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// this is to save DOM nodes and avoid using up too much memory.
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// See: https://github.com/tootsuite/mastodon/issues/2900
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this.setState((prevState) => ({ isHidden: !prevState.isIntersecting }));
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}
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handleRef = (node) => {
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this.node = node;
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}
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render () {
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const { children, id, index, listLength } = this.props;
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const { isIntersecting, isHidden } = this.state;
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if (!isIntersecting && isHidden) {
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return (
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<article
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ref={this.handleRef}
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aria-posinset={index}
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aria-setsize={listLength}
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style={{ height: `${this.height}px`, opacity: 0, overflow: 'hidden' }}
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data-id={id}
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tabIndex='0'
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>
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{children && React.cloneElement(children, { hidden: true })}
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</article>
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);
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}
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return (
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<article ref={this.handleRef} aria-posinset={index} aria-setsize={listLength} data-id={id} tabIndex='0'>
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{children && React.cloneElement(children, { hidden: false })}
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</article>
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);
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}
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}
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@ -0,0 +1,179 @@
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import React, { PureComponent } from 'react';
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import { ScrollContainer } from 'react-router-scroll';
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import PropTypes from 'prop-types';
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import IntersectionObserverArticle from './intersection_observer_article';
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import LoadMore from './load_more';
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import IntersectionObserverWrapper from '../features/ui/util/intersection_observer_wrapper';
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import { throttle } from 'lodash';
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export default class ScrollableList extends PureComponent {
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static propTypes = {
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scrollKey: PropTypes.string.isRequired,
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onScrollToBottom: PropTypes.func,
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onScrollToTop: PropTypes.func,
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onScroll: PropTypes.func,
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trackScroll: PropTypes.bool,
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shouldUpdateScroll: PropTypes.func,
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isLoading: PropTypes.bool,
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hasMore: PropTypes.bool,
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prepend: PropTypes.node,
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emptyMessage: PropTypes.node,
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children: PropTypes.node,
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};
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static defaultProps = {
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trackScroll: true,
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};
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intersectionObserverWrapper = new IntersectionObserverWrapper();
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handleScroll = throttle(() => {
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if (this.node) {
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const { scrollTop, scrollHeight, clientHeight } = this.node;
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const offset = scrollHeight - scrollTop - clientHeight;
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this._oldScrollPosition = scrollHeight - scrollTop;
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if (400 > offset && this.props.onScrollToBottom && !this.props.isLoading) {
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this.props.onScrollToBottom();
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} else if (scrollTop < 100 && this.props.onScrollToTop) {
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this.props.onScrollToTop();
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} else if (this.props.onScroll) {
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this.props.onScroll();
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}
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}
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}, 150, {
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trailing: true,
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});
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componentDidMount () {
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this.attachScrollListener();
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this.attachIntersectionObserver();
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// Handle initial scroll posiiton
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this.handleScroll();
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}
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componentDidUpdate (prevProps) {
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// Reset the scroll position when a new child comes in in order not to
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// jerk the scrollbar around if you're already scrolled down the page.
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if (React.Children.count(prevProps.children) < React.Children.count(this.props.children) && this._oldScrollPosition && this.node.scrollTop > 0) {
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if (this.getFirstChildKey(prevProps) !== this.getFirstChildKey(this.props)) {
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const newScrollTop = this.node.scrollHeight - this._oldScrollPosition;
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if (this.node.scrollTop !== newScrollTop) {
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this.node.scrollTop = newScrollTop;
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}
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} else {
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this._oldScrollPosition = this.node.scrollHeight - this.node.scrollTop;
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}
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}
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}
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componentWillUnmount () {
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this.detachScrollListener();
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this.detachIntersectionObserver();
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}
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attachIntersectionObserver () {
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this.intersectionObserverWrapper.connect({
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root: this.node,
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rootMargin: '300% 0px',
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});
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}
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detachIntersectionObserver () {
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this.intersectionObserverWrapper.disconnect();
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}
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attachScrollListener () {
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this.node.addEventListener('scroll', this.handleScroll);
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}
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detachScrollListener () {
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this.node.removeEventListener('scroll', this.handleScroll);
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}
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getFirstChildKey (props) {
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const { children } = props;
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const firstChild = Array.isArray(children) ? children[0] : children;
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return firstChild && firstChild.key;
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}
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setRef = (c) => {
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this.node = c;
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}
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handleLoadMore = (e) => {
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e.preventDefault();
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this.props.onScrollToBottom();
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}
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handleKeyDown = (e) => {
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if (['PageDown', 'PageUp'].includes(e.key) || (e.ctrlKey && ['End', 'Home'].includes(e.key))) {
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const article = (() => {
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switch (e.key) {
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case 'PageDown':
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return e.target.nodeName === 'ARTICLE' && e.target.nextElementSibling;
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case 'PageUp':
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return e.target.nodeName === 'ARTICLE' && e.target.previousElementSibling;
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case 'End':
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return this.node.querySelector('[role="feed"] > article:last-of-type');
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case 'Home':
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return this.node.querySelector('[role="feed"] > article:first-of-type');
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default:
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return null;
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}
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})();
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if (article) {
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e.preventDefault();
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article.focus();
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article.scrollIntoView();
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}
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}
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}
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render () {
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const { children, scrollKey, trackScroll, shouldUpdateScroll, isLoading, hasMore, prepend, emptyMessage } = this.props;
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const childrenCount = React.Children.count(children);
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const loadMore = <LoadMore visible={!isLoading && childrenCount > 0 && hasMore} onClick={this.handleLoadMore} />;
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let scrollableArea = null;
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if (isLoading || childrenCount > 0 || !emptyMessage) {
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scrollableArea = (
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<div className='scrollable' ref={this.setRef}>
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<div role='feed' className='item-list' onKeyDown={this.handleKeyDown}>
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{prepend}
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{React.Children.map(this.props.children, (child, index) => (
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<IntersectionObserverArticle key={child.key} id={child.key} index={index} listLength={childrenCount} intersectionObserverWrapper={this.intersectionObserverWrapper}>
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{child}
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</IntersectionObserverArticle>
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))}
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{loadMore}
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</div>
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</div>
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);
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} else {
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scrollableArea = (
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<div className='empty-column-indicator' ref={this.setRef}>
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{emptyMessage}
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</div>
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);
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}
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if (trackScroll) {
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return (
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<ScrollContainer scrollKey={scrollKey} shouldUpdateScroll={shouldUpdateScroll}>
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{scrollableArea}
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</ScrollContainer>
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);
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} else {
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return scrollableArea;
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}
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}
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}
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