diff options
Diffstat (limited to 'app/javascript/flavours/glitch/components/scrollable_list.js')
-rw-r--r-- | app/javascript/flavours/glitch/components/scrollable_list.js | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/app/javascript/flavours/glitch/components/scrollable_list.js b/app/javascript/flavours/glitch/components/scrollable_list.js new file mode 100644 index 000000000..16f13afa4 --- /dev/null +++ b/app/javascript/flavours/glitch/components/scrollable_list.js @@ -0,0 +1,354 @@ +import React, { PureComponent } from 'react'; +import ScrollContainer from 'flavours/glitch/containers/scroll_container'; +import PropTypes from 'prop-types'; +import IntersectionObserverArticleContainer from 'flavours/glitch/containers/intersection_observer_article_container'; +import LoadMore from './load_more'; +import LoadPending from './load_pending'; +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'; +import { connect } from 'react-redux'; + +const MOUSE_IDLE_DELAY = 300; + +const mapStateToProps = (state, { scrollKey }) => { + return { + preventScroll: scrollKey === state.getIn(['dropdown_menu', 'scroll_key']), + }; +}; + +export default @connect(mapStateToProps, null, null, { forwardRef: true }) +class ScrollableList extends PureComponent { + + static contextTypes = { + router: PropTypes.object, + }; + + 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 (400 > offset && 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; + + setScrollTop = newScrollTop => { + if (this.getScrollTop() !== newScrollTop) { + this.lastScrollWasSynthetic = true; + + if (this.props.bindToDocument) { + document.scrollingElement.scrollTop = newScrollTop; + } else { + this.node.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 posiiton + this.handleScroll(); + } + + getScrollPosition = () => { + if (this.node && (this.getScrollTop() > 0 || this.mouseMovedRecently)) { + return { height: this.getScrollHeight(), top: this.getScrollTop() }; + } else { + return null; + } + } + + getScrollTop = () => { + return this.props.bindToDocument ? document.scrollingElement.scrollTop : this.node.scrollTop; + } + + getScrollHeight = () => { + return this.props.bindToDocument ? document.scrollingElement.scrollHeight : this.node.scrollHeight; + } + + getClientHeight = () => { + return this.props.bindToDocument ? document.scrollingElement.clientHeight : this.node.clientHeight; + } + + updateScrollBottom = (snapshot) => { + const newScrollTop = this.getScrollHeight() - snapshot; + + this.setScrollTop(newScrollTop); + } + + cacheMediaWidth = (width) => { + if (width && this.state.cachedMediaWidth != width) this.setState({ cachedMediaWidth: width }); + } + + 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); + 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); + } + } + + componentWillUnmount () { + this.clearMouseIdleTimer(); + 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 () { + if (this.props.bindToDocument) { + document.addEventListener('scroll', this.handleScroll); + document.addEventListener('wheel', this.handleWheel); + } else { + this.node.addEventListener('scroll', this.handleScroll); + this.node.addEventListener('wheel', this.handleWheel); + } + } + + detachScrollListener () { + if (this.props.bindToDocument) { + document.removeEventListener('scroll', this.handleScroll); + document.removeEventListener('wheel', this.handleWheel); + } else { + this.node.removeEventListener('scroll', this.handleScroll); + this.node.removeEventListener('wheel', this.handleWheel); + } + } + + 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 = React.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} + + {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, + cachedMediaWidth: this.state.cachedMediaWidth, + cacheMediaWidth: this.cacheMediaWidth, + })} + </IntersectionObserverArticleContainer> + ))} + + {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; + } + } + +} |