Add JSDoc comments to timeline components

app/soapbox/components/scroll-top-button.tsx

@@ -9,13 +9,19 @@ import { useSettings } from 'soapbox/hooks';
 import { shortNumberFormat } from 'soapbox/utils/numbers';
 
 interface IScrollTopButton {
+  /** Callback when clicked, and also when scrolled to the top. */
   onClick: () => void,
+  /** Number of unread items. */
   count: number,
+  /** Message to display in the button (should contain a `{count}` value). */
   message: MessageDescriptor,
+  /** Distance from the top of the screen (scrolling down) before the button appears. */
   threshold?: number,
+  /** Distance from the top of the screen (scrolling up) before the action is triggered. */
   autoloadThreshold?: number,
 }
 
+/** Floating new post counter above timelines, clicked to scroll to top. */
 const ScrollTopButton: React.FC<IScrollTopButton> = ({
   onClick,
   count,
@@ -41,7 +47,7 @@ const ScrollTopButton: React.FC<IScrollTopButton> = ({
     } else {
       setScrolled(false);
     }
-  }, 150, { trailing: true }), []);
+  }, 150, { trailing: true }), [autoload, threshold, autoloadThreshold]);
 
   const scrollUp = () => {
     window.scrollTo({ top: 0, behavior: 'smooth' });

app/soapbox/components/scrollable_list.tsx

@@ -9,6 +9,7 @@ import { useSettings } from 'soapbox/hooks';
 import LoadMore from './load_more';
 import { Spinner, Text } from './ui';
 
+/** Custom Viruoso component context. */
 type Context = {
   itemClassName?: string,
   listClassName?: string,
@@ -20,6 +21,7 @@ type SavedScrollPosition = {
   offset: number,
 }
 
+/** Custom Virtuoso Item component representing a single scrollable item. */
 // NOTE: It's crucial to space lists with **padding** instead of margin!
 // Pass an `itemClassName` like `pb-3`, NOT a `space-y-3` className
 // https://virtuoso.dev/troubleshooting#list-does-not-scroll-to-the-bottom--items-jump-around
@@ -27,6 +29,7 @@ const Item: Components<Context>['Item'] = ({ context, ...rest }) => (
   <div className={context?.itemClassName} {...rest} />
 );
 
+/** Custom Virtuoso List component for the outer container. */
 // Ensure the className winds up here
 const List: Components<Context>['List'] = React.forwardRef((props, ref) => {
   const { context, ...rest } = props;
@@ -34,28 +37,47 @@ const List: Components<Context>['List'] = React.forwardRef((props, ref) => {
 });
 
 interface IScrollableList extends VirtuosoProps<any, any> {
+  /** Unique key to preserve the scroll position when navigating back. */
   scrollKey?: string,
+  /** Pagination callback when the end of the list is reached. */
   onLoadMore?: () => void,
+  /** Whether the data is currently being fetched. */
   isLoading?: boolean,
+  /** Whether to actually display the loading state. */
   showLoading?: boolean,
+  /** Whether we expect an additional page of data. */
   hasMore?: boolean,
+  /** Additional element to display at the top of the list. */
   prepend?: React.ReactNode,
+  /** Whether to display the prepended element. */
   alwaysPrepend?: boolean,
+  /** Message to display when the list is loaded but empty. */
   emptyMessage?: React.ReactNode,
+  /** Scrollable content. */
   children: Iterable<React.ReactNode>,
+  /** Callback when the list is scrolled to the top. */
   onScrollToTop?: () => void,
+  /** Callback when the list is scrolled. */
   onScroll?: () => void,
+  /** Placeholder component to render while loading. */
   placeholderComponent?: React.ComponentType | React.NamedExoticComponent,
+  /** Number of placeholders to render while loading. */
   placeholderCount?: number,
+  /** Pull to refresh callback. */
   onRefresh?: () => Promise<any>,
+  /** Extra class names on the Virtuoso element. */
   className?: string,
+  /** Class names on each item container. */
   itemClassName?: string,
+  /** `id` attribute on the Virtuoso element. */
   id?: string,
+  /** CSS styles on the Virtuoso element. */
   style?: React.CSSProperties,
+  /** Whether to use the window to scroll the content instead of Virtuoso's container. */
   useWindowScroll?: boolean
 }
 
-/** Legacy ScrollableList with Virtuoso for backwards-compatibility */
+/** Legacy ScrollableList with Virtuoso for backwards-compatibility. */
 const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
   scrollKey,
   prepend = null,
@@ -88,7 +110,7 @@ const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
   const topIndex = useRef<number>(scrollData ? scrollData.index : 0);
   const topOffset = useRef<number>(scrollData ? scrollData.offset : 0);
 
-  /** Normalized children */
+  /** Normalized children. */
   const elements = Array.from(children || []);
 
   const showPlaceholder = showLoading && Placeholder && placeholderCount > 0;
@@ -129,7 +151,7 @@ const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
     };
   }, []);
 
-  /* Render an empty state instead of the scrollable list */
+  /* Render an empty state instead of the scrollable list. */
   const renderEmpty = (): JSX.Element => {
     return (
       <div className='mt-2'>
@@ -146,7 +168,7 @@ const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
     );
   };
 
-  /** Render a single item */
+  /** Render a single item. */
   const renderItem = (_i: number, element: JSX.Element): JSX.Element => {
     if (showPlaceholder) {
       return <Placeholder />;
@@ -192,7 +214,7 @@ const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
     return 0;
   }, [showLoading, initialTopMostItemIndex]);
 
-  /** Render the actual Virtuoso list */
+  /** Render the actual Virtuoso list. */
   const renderFeed = (): JSX.Element => (
     <Virtuoso
       ref={ref}
@@ -222,7 +244,7 @@ const ScrollableList = React.forwardRef<VirtuosoHandle, IScrollableList>(({
     />
   );
 
-  /** Conditionally render inner elements */
+  /** Conditionally render inner elements. */
   const renderBody = (): JSX.Element => {
     if (isEmpty) {
       return renderEmpty();

app/soapbox/components/status_list.tsx

@@ -14,24 +14,31 @@ import type { VirtuosoHandle } from 'react-virtuoso';
 import type { IScrollableList } from 'soapbox/components/scrollable_list';
 
 interface IStatusList extends Omit<IScrollableList, 'onLoadMore' | 'children'> {
+  /** Unique key to preserve the scroll position when navigating back. */
   scrollKey: string,
+  /** List of status IDs to display. */
   statusIds: ImmutableOrderedSet<string>,
+  /** Last _unfiltered_ status ID (maxId) for pagination.  */
   lastStatusId?: string,
+  /** Pinned statuses to show at the top of the feed. */
   featuredStatusIds?: ImmutableOrderedSet<string>,
+  /** Pagination callback when the end of the list is reached. */
   onLoadMore?: (lastStatusId: string) => void,
+  /** Whether the data is currently being fetched. */
   isLoading: boolean,
+  /** Whether the server did not return a complete page. */
   isPartial?: boolean,
+  /** Whether we expect an additional page of data. */
   hasMore: boolean,
-  prepend?: React.ReactNode,
+  /** Message to display when the list is loaded but empty. */
   emptyMessage: React.ReactNode,
-  alwaysPrepend?: boolean,
+  /** ID of the timeline in Redux. */
   timelineId?: string,
-  queuedItemSize?: number,
-  onScrollToTop?: () => void,
-  onScroll?: () => void,
+  /** Whether to display a gap or border between statuses in the list. */
   divideType: 'space' | 'border',
 }
 
+/** Feed of statuses, built atop ScrollableList. */
 const StatusList: React.FC<IStatusList> = ({
   statusIds,
   lastStatusId,

app/soapbox/features/ui/components/timeline.tsx

@@ -15,9 +15,11 @@ const messages = defineMessages({
 });
 
 interface ITimeline extends Omit<IStatusList, 'statusIds' | 'isLoading' | 'hasMore'> {
+  /** ID of the timeline in Redux. */
   timelineId: string,
 }
 
+/** Scrollable list of statuses from a timeline in the Redux store. */
 const Timeline: React.FC<ITimeline> = ({
   timelineId,
   onLoadMore,
@@ -55,6 +57,7 @@ const Timeline: React.FC<ITimeline> = ({
       />
 
       <StatusList
+        timelineId={timelineId}
         onScrollToTop={handleScrollToTop}
         onScroll={handleScroll}
         lastStatusId={lastStatusId}