Generalized the infinite scrollable list (#4697)

app/javascript/mastodon/components/status_list.js

@@ -1,12 +1,9 @@
 import React from 'react';
 import ImmutablePropTypes from 'react-immutable-proptypes';
-import { ScrollContainer } from 'react-router-scroll';
 import PropTypes from 'prop-types';
 import StatusContainer from '../containers/status_container';
-import LoadMore from './load_more';
 import ImmutablePureComponent from 'react-immutable-pure-component';
-import IntersectionObserverWrapper from '../features/ui/util/intersection_observer_wrapper';
-import { throttle } from 'lodash';
+import ScrollableList from './scrollable_list';
 
 export default class StatusList extends ImmutablePureComponent {
 
@@ -28,145 +25,21 @@ export default class StatusList extends ImmutablePureComponent {
     trackScroll: true,
   };
 
-  intersectionObserverWrapper = new IntersectionObserverWrapper();
-
-  handleScroll = throttle(() => {
-    if (this.node) {
-      const { scrollTop, scrollHeight, clientHeight } = this.node;
-      const offset = scrollHeight - scrollTop - clientHeight;
-      this._oldScrollPosition = scrollHeight - scrollTop;
-
-      if (400 > offset && this.props.onScrollToBottom && !this.props.isLoading) {
-        this.props.onScrollToBottom();
-      } else 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();
-
-    // Handle initial scroll posiiton
-    this.handleScroll();
-  }
-
-  componentDidUpdate (prevProps) {
-    // Reset the scroll position when a new toot comes in in order not to
-    // jerk the scrollbar around if you're already scrolled down the page.
-    if (prevProps.statusIds.size < this.props.statusIds.size && this._oldScrollPosition && this.node.scrollTop > 0) {
-      if (prevProps.statusIds.first() !== this.props.statusIds.first()) {
-        let newScrollTop = this.node.scrollHeight - this._oldScrollPosition;
-        if (this.node.scrollTop !== newScrollTop) {
-          this.node.scrollTop = newScrollTop;
-        }
-      } else {
-        this._oldScrollPosition = this.node.scrollHeight - this.node.scrollTop;
-      }
-    }
-  }
-
-  componentWillUnmount () {
-    this.detachScrollListener();
-    this.detachIntersectionObserver();
-  }
-
-  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);
-  }
-
-  setRef = (c) => {
-    this.node = c;
-  }
-
-  handleLoadMore = (e) => {
-    e.preventDefault();
-    this.props.onScrollToBottom();
-  }
-
-  handleKeyDown = (e) => {
-    if (['PageDown', 'PageUp'].includes(e.key) || (e.ctrlKey && ['End', 'Home'].includes(e.key))) {
-      const article = (() => {
-        switch (e.key) {
-        case 'PageDown':
-          return e.target.nodeName === 'ARTICLE' && e.target.nextElementSibling;
-        case 'PageUp':
-          return e.target.nodeName === 'ARTICLE' && e.target.previousElementSibling;
-        case 'End':
-          return this.node.querySelector('[role="feed"] > article:last-of-type');
-        case 'Home':
-          return this.node.querySelector('[role="feed"] > article:first-of-type');
-        default:
-          return null;
-        }
-      })();
-
-
-      if (article) {
-        e.preventDefault();
-        article.focus();
-        article.scrollIntoView();
-      }
-    }
-  }
-
   render () {
-    const { statusIds, scrollKey, trackScroll, shouldUpdateScroll, isLoading, hasMore, prepend, emptyMessage } = this.props;
+    const { statusIds, ...other } = this.props;
+    const { isLoading } = other;
 
-    const loadMore     = <LoadMore visible={!isLoading && statusIds.size > 0 && hasMore} onClick={this.handleLoadMore} />;
-    let scrollableArea = null;
+    const scrollableContent = (isLoading || statusIds.size > 0) ? (
+      statusIds.map((statusId) => (
+        <StatusContainer key={statusId} id={statusId} />
+      ))
+    ) : null;
 
-    if (isLoading || statusIds.size > 0 || !emptyMessage) {
-      scrollableArea = (
-        <div className='scrollable' ref={this.setRef}>
-          <div role='feed' className='status-list' onKeyDown={this.handleKeyDown}>
-            {prepend}
-
-            {statusIds.map((statusId, index) => {
-              return <StatusContainer key={statusId} id={statusId} index={index} listLength={statusIds.size} intersectionObserverWrapper={this.intersectionObserverWrapper} />;
-            })}
-
-            {loadMore}
-          </div>
-        </div>
-      );
-    } else {
-      scrollableArea = (
-        <div className='empty-column-indicator' ref={this.setRef}>
-          {emptyMessage}
-        </div>
-      );
-    }
-
-    if (trackScroll) {
-      return (
-        <ScrollContainer scrollKey={scrollKey} shouldUpdateScroll={shouldUpdateScroll}>
-          {scrollableArea}
-        </ScrollContainer>
-      );
-    } else {
-      return scrollableArea;
-    }
+    return (
+      <ScrollableList {...other}>
+        {scrollableContent}
+      </ScrollableList>
+    );
   }
 
 }