Add option to disable real-time updates in web UI (#9984)

Fix #9031
Fix #7913

app/javascript/mastodon/components/load_pending.js

@@ -0,0 +1,22 @@
+import React from 'react';
+import { FormattedMessage } from 'react-intl';
+import PropTypes from 'prop-types';
+
+export default class LoadPending extends React.PureComponent {
+
+  static propTypes = {
+    onClick: PropTypes.func,
+    count: PropTypes.number,
+  }
+
+  render() {
+    const { count } = this.props;
+
+    return (
+      <button className='load-more load-gap' onClick={this.props.onClick}>
+        <FormattedMessage id='load_pending' defaultMessage='{count, plural, one {# new item} other {# new items}}' values={{ count }} />
+      </button>
+    );
+  }
+
+}

app/javascript/mastodon/components/scrollable_list.js

@@ -3,6 +3,7 @@ import { ScrollContainer } from 'react-router-scroll-4';
 import PropTypes from 'prop-types';
 import IntersectionObserverArticleContainer from '../containers/intersection_observer_article_container';
 import LoadMore from './load_more';
+import LoadPending from './load_pending';
 import IntersectionObserverWrapper from '../features/ui/util/intersection_observer_wrapper';
 import { throttle } from 'lodash';
 import { List as ImmutableList } from 'immutable';
@@ -21,6 +22,7 @@ export default 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,
@@ -28,6 +30,7 @@ export default class ScrollableList extends PureComponent {
     isLoading: PropTypes.bool,
     showLoading: PropTypes.bool,
     hasMore: PropTypes.bool,
+    numPending: PropTypes.number,
     prepend: PropTypes.node,
     alwaysPrepend: PropTypes.bool,
     emptyMessage: PropTypes.node,
@@ -225,12 +228,18 @@ export default class ScrollableList extends PureComponent {
     this.props.onLoadMore();
   }
 
+  handleLoadPending = e => {
+    e.preventDefault();
+    this.props.onLoadPending();
+  }
+
   render () {
-    const { children, scrollKey, trackScroll, shouldUpdateScroll, showLoading, isLoading, hasMore, prepend, alwaysPrepend, emptyMessage, onLoadMore } = this.props;
+    const { children, scrollKey, trackScroll, shouldUpdateScroll, showLoading, isLoading, hasMore, numPending, prepend, alwaysPrepend, 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) {
@@ -251,6 +260,8 @@ export default class ScrollableList extends PureComponent {
           <div role='feed' className='item-list'>
             {prepend}
 
+            {loadPending}
+
             {React.Children.map(this.props.children, (child, index) => (
               <IntersectionObserverArticleContainer
                 key={child.key}