Refactor virtualizer layouts to remove Spectrum-specific logic and improve backward compatibility

packages/@react-aria/dnd/stories/VirtualizedListBox.tsx

@@ -137,10 +137,7 @@ export const VirtualizedListBox = React.forwardRef(function (props: any, ref) {
 
   let layout = React.useMemo(() =>
     new ListLayout<unknown>({
-      estimatedRowHeight: 32,
-      padding: 8,
-      loaderHeight: 40,
-      placeholderHeight: 32
+      estimatedRowHeight: 32
     })
   , []);
 

packages/@react-aria/grid/src/GridKeyboardDelegate.ts

@@ -10,7 +10,7 @@
  * governing permissions and limitations under the License.
  */
 
-import {Direction, DisabledBehavior, Key, KeyboardDelegate, LayoutDelegate, Node} from '@react-types/shared';
+import {Direction, DisabledBehavior, Key, KeyboardDelegate, LayoutDelegate, Node, Rect, Size} from '@react-types/shared';
 import {DOMLayoutDelegate} from '@react-aria/selection';
 import {getChildNodes, getFirstItem, getLastItem, getNthItem} from '@react-stately/collections';
 import {GridCollection} from '@react-types/grid';
@@ -24,6 +24,8 @@ export interface GridKeyboardDelegateOptions<C> {
   direction: Direction,
   collator?: Intl.Collator,
   layoutDelegate?: LayoutDelegate,
+  /** @deprecated - Use layoutDelegate instead. */
+  layout?: DeprecatedLayout,
   focusMode?: 'row' | 'cell'
 }
 
@@ -42,7 +44,7 @@ export class GridKeyboardDelegate<T, C extends GridCollection<T>> implements Key
     this.disabledBehavior = options.disabledBehavior || 'all';
     this.direction = options.direction;
     this.collator = options.collator;
-    this.layoutDelegate = options.layoutDelegate || new DOMLayoutDelegate(options.ref);
+    this.layoutDelegate = options.layoutDelegate || (options.layout ? new DeprecatedLayoutDelegate(options.layout) : new DOMLayoutDelegate(options.ref));
     this.focusMode = options.focusMode || 'row';
   }
 
@@ -356,3 +358,38 @@ export class GridKeyboardDelegate<T, C extends GridCollection<T>> implements Key
     return null;
   }
 }
+
+/* Backward compatibility for old Virtualizer Layout interface. */
+interface DeprecatedLayout {
+  getLayoutInfo(key: Key): DeprecatedLayoutInfo,
+  getContentSize(): Size,
+  virtualizer: DeprecatedVirtualizer
+}
+
+interface DeprecatedLayoutInfo {
+  rect: Rect
+}
+
+interface DeprecatedVirtualizer {
+  visibleRect: Rect
+}
+
+class DeprecatedLayoutDelegate implements LayoutDelegate {
+  layout: DeprecatedLayout;
+
+  constructor(layout: DeprecatedLayout) {
+    this.layout = layout;
+  }
+
+  getContentSize(): Size {
+    return this.layout.getContentSize();
+  }
+
+  getItemRect(key: Key): Rect | null {
+    return this.layout.getLayoutInfo(key)?.rect || null;
+  }
+
+  getVisibleRect(): Rect {
+    return this.layout.virtualizer.visibleRect;
+  }
+}

packages/@react-aria/table/src/useTable.ts

@@ -15,7 +15,7 @@ import {GridAria, GridProps, useGrid} from '@react-aria/grid';
 import {gridIds} from './utils';
 // @ts-ignore
 import intlMessages from '../intl/*.json';
-import {LayoutDelegate} from '@react-types/shared';
+import {Key, LayoutDelegate, Rect, Size} from '@react-types/shared';
 import {mergeProps, useDescription, useId, useUpdateEffect} from '@react-aria/utils';
 import {RefObject, useMemo} from 'react';
 import {TableKeyboardDelegate} from './TableKeyboardDelegate';
@@ -25,7 +25,23 @@ import {useCollator, useLocale, useLocalizedStringFormatter} from '@react-aria/i
 
 export interface AriaTableProps extends GridProps {
   /** The layout object for the table. Computes what content is visible and how to position and style them. */
-  layoutDelegate?: LayoutDelegate
+  layoutDelegate?: LayoutDelegate,
+  /** @deprecated - Use layoutDelegate instead. */
+  layout?: DeprecatedLayout
+}
+
+interface DeprecatedLayout {
+  getLayoutInfo(key: Key): DeprecatedLayoutInfo,
+  getContentSize(): Size,
+  virtualizer: DeprecatedVirtualizer
+}
+
+interface DeprecatedLayoutInfo {
+  rect: Rect
+}
+
+interface DeprecatedVirtualizer {
+  visibleRect: Rect
 }
 
 /**
@@ -40,7 +56,8 @@ export function useTable<T>(props: AriaTableProps, state: TableState<T> | TreeGr
   let {
     keyboardDelegate,
     isVirtualized,
-    layoutDelegate
+    layoutDelegate,
+    layout
   } = props;
 
   // By default, a KeyboardDelegate is provided which uses the DOM to query layout information (e.g. for page up/page down).
@@ -55,8 +72,9 @@ export function useTable<T>(props: AriaTableProps, state: TableState<T> | TreeGr
     ref,
     direction,
     collator,
-    layoutDelegate
-  }), [keyboardDelegate, state.collection, state.disabledKeys, disabledBehavior, ref, direction, collator, layoutDelegate]);
+    layoutDelegate,
+    layout
+  }), [keyboardDelegate, state.collection, state.disabledKeys, disabledBehavior, ref, direction, collator, layoutDelegate, layout]);
   let id = useId(props.id);
   gridIds.set(state, id);
 

packages/@react-aria/virtualizer/src/VirtualizerItem.tsx

@@ -74,9 +74,7 @@ export function layoutInfoToStyle(layoutInfo: LayoutInfo, dir: Direction, parent
     position: layoutInfo.isSticky ? 'sticky' : 'absolute',
     // Sticky elements are positioned in normal document flow. Display inline-block so that they don't push other sticky columns onto the following rows.
     display: layoutInfo.isSticky ? 'inline-block' : undefined,
-    // Use clip instead of hidden to avoid creating an implicit generic container in the accessibility tree in Firefox.
-    // Hidden still allows programmatic scrolling whereas clip does not.
-    overflow: layoutInfo.allowOverflow ? 'visible' : 'clip',
+    overflow: layoutInfo.allowOverflow ? 'visible' : 'hidden',
     opacity: layoutInfo.opacity,
     zIndex: layoutInfo.zIndex,
     transform: layoutInfo.transform,

packages/@react-spectrum/list/package.json

@@ -54,6 +54,7 @@
     "@react-stately/collections": "^3.10.7",
     "@react-stately/layout": "^3.13.9",
     "@react-stately/list": "^3.10.5",
+    "@react-stately/virtualizer": "^3.7.1",
     "@react-types/grid": "^3.2.6",
     "@react-types/shared": "^3.23.1",
     "@spectrum-icons/ui": "^3.6.7",

packages/@react-spectrum/list/src/ListView.tsx

@@ -22,10 +22,10 @@ import InsertionIndicator from './InsertionIndicator';
 // @ts-ignore
 import intlMessages from '../intl/*.json';
 import {ListKeyboardDelegate} from '@react-aria/selection';
-import {ListLayout} from '@react-stately/layout';
 import {ListState, useListState} from '@react-stately/list';
 import listStyles from './styles.css';
 import {ListViewItem} from './ListViewItem';
+import {ListViewLayout} from './ListViewLayout';
 import {ProgressCircle} from '@react-spectrum/progress';
 import React, {JSX, ReactElement, useCallback, useContext, useEffect, useMemo, useRef, useState} from 'react';
 import RootDropIndicator from './RootDropIndicator';
@@ -70,7 +70,7 @@ interface ListViewContextValue<T> {
   onAction:(key: Key) => void,
   isListDraggable: boolean,
   isListDroppable: boolean,
-  layout: ListLayout<T>,
+  layout: ListViewLayout<T>,
   loadingState: LoadingState,
   renderEmptyState?: () => JSX.Element
 }
@@ -94,16 +94,12 @@ const ROW_HEIGHTS = {
 
 function useListLayout<T>(state: ListState<T>, density: SpectrumListViewProps<T>['density'], overflowMode: SpectrumListViewProps<T>['overflowMode']) {
   let {scale} = useProvider();
-  let isEmpty = state.collection.size === 0;
   let layout = useMemo(() =>
-    new ListLayout<T>({
-      estimatedRowHeight: ROW_HEIGHTS[density][scale],
-      padding: 0,
-      loaderHeight: isEmpty ? null : ROW_HEIGHTS[density][scale],
-      enableEmptyState: true
+    new ListViewLayout<T>({
+      estimatedRowHeight: ROW_HEIGHTS[density][scale]
     })
     // eslint-disable-next-line react-hooks/exhaustive-deps
-    , [scale, density, isEmpty, overflowMode]);
+    , [scale, density, overflowMode]);
 
   return layout;
 }

packages/@react-spectrum/list/src/ListViewLayout.ts

@@ -0,0 +1,55 @@
+import {InvalidationContext, LayoutInfo, Rect} from '@react-stately/virtualizer';
+import {LayoutNode, ListLayout} from '@react-stately/layout';
+import {Node} from '@react-types/shared';
+
+interface ListViewLayoutProps {
+  isLoading?: boolean
+}
+
+export class ListViewLayout<T> extends ListLayout<T, ListViewLayoutProps> {
+  private isLoading: boolean = false;
+
+  validate(invalidationContext: InvalidationContext<ListViewLayoutProps>): void {
+    this.isLoading = invalidationContext.layoutOptions?.isLoading || false;
+    super.validate(invalidationContext);
+  }
+
+  protected buildCollection(): LayoutNode[] {
+    let nodes = super.buildCollection();
+    let y = this.contentSize.height;
+
+    if (this.isLoading) {
+      let rect = new Rect(0, y, this.virtualizer.visibleRect.width, nodes.length === 0 ? this.virtualizer.visibleRect.height : this.estimatedRowHeight);
+      let loader = new LayoutInfo('loader', 'loader', rect);
+      let node = {
+        layoutInfo: loader,
+        validRect: loader.rect
+      };
+      nodes.push(node);
+      this.layoutNodes.set(loader.key, node);
+      y = loader.rect.maxY;
+    }
+
+    if (nodes.length === 0) {
+      let rect = new Rect(0, y, this.virtualizer.visibleRect.width, this.virtualizer.visibleRect.height);
+      let placeholder = new LayoutInfo('placeholder', 'placeholder', rect);
+      let node = {
+        layoutInfo: placeholder,
+        validRect: placeholder.rect
+      };
+      nodes.push(node);
+      this.layoutNodes.set(placeholder.key, node);
+      y = placeholder.rect.maxY;
+    }
+
+    this.contentSize.height = y;
+    return nodes;
+  }
+
+  protected buildItem(node: Node<T>, x: number, y: number): LayoutNode {
+    let res = super.buildItem(node, x, y);
+    // allow overflow so the focus ring/selection ring can extend outside to overlap with the adjacent items borders
+    res.layoutInfo.allowOverflow = true;
+    return res;
+  }
+}

packages/@react-spectrum/listbox/src/ListBoxBase.tsx

@@ -17,9 +17,9 @@ import {FocusScope} from '@react-aria/focus';
 // @ts-ignore
 import intlMessages from '../intl/*.json';
 import {ListBoxContext} from './ListBoxContext';
+import {ListBoxLayout} from './ListBoxLayout';
 import {ListBoxOption} from './ListBoxOption';
 import {ListBoxSection} from './ListBoxSection';
-import {ListLayout} from '@react-stately/layout';
 import {ListState} from '@react-stately/list';
 import {mergeProps} from '@react-aria/utils';
 import {ProgressCircle} from '@react-spectrum/progress';
@@ -31,7 +31,7 @@ import {useProvider} from '@react-spectrum/provider';
 import {Virtualizer, VirtualizerItem} from '@react-aria/virtualizer';
 
 interface ListBoxBaseProps<T> extends AriaListBoxOptions<T>, DOMProps, AriaLabelingProps, StyleProps {
-  layout: ListLayout<T>,
+  layout: ListBoxLayout<T>,
   state: ListState<T>,
   autoFocus?: boolean | FocusStrategy,
   shouldFocusWrap?: boolean,
@@ -48,17 +48,14 @@ interface ListBoxBaseProps<T> extends AriaListBoxOptions<T>, DOMProps, AriaLabel
 }
 
 /** @private */
-export function useListBoxLayout<T>(): ListLayout<T> {
+export function useListBoxLayout<T>(): ListBoxLayout<T> {
   let {scale} = useProvider();
   let layout = useMemo(() =>
-    new ListLayout<T>({
+    new ListBoxLayout<T>({
       estimatedRowHeight: scale === 'large' ? 48 : 32,
       estimatedHeadingHeight: scale === 'large' ? 33 : 26,
       padding: scale === 'large' ? 5 : 4, // TODO: get from DNA
-      loaderHeight: 40,
-      placeholderHeight: scale === 'large' ? 48 : 32,
-      forceSectionHeaders: true,
-      enableEmptyState: true
+      placeholderHeight: scale === 'large' ? 48 : 32
     })
   , [scale]);
 

packages/@react-spectrum/listbox/src/ListBoxLayout.ts

@@ -0,0 +1,87 @@
+import {InvalidationContext, LayoutInfo, Rect} from '@react-stately/virtualizer';
+import {LayoutNode, ListLayout, ListLayoutOptions} from '@react-stately/layout';
+import {Node} from '@react-types/shared';
+
+interface ListBoxLayoutProps {
+  isLoading?: boolean
+}
+
+interface ListBoxLayoutOptions extends ListLayoutOptions {
+  placeholderHeight: number,
+  padding: number
+}
+
+export class ListBoxLayout<T> extends ListLayout<T, ListBoxLayoutProps> {
+  private isLoading: boolean = false;
+  private placeholderHeight: number;
+  private padding: number;
+
+  constructor(opts: ListBoxLayoutOptions) {
+    super(opts);
+    this.placeholderHeight = opts.placeholderHeight;
+    this.padding = opts.padding;
+  }
+
+  validate(invalidationContext: InvalidationContext<ListBoxLayoutProps>): void {
+    this.isLoading = invalidationContext.layoutOptions?.isLoading || false;
+    super.validate(invalidationContext);
+  }
+
+  protected buildCollection(): LayoutNode[] {
+    let nodes = super.buildCollection(this.padding);
+    let y = this.contentSize.height;
+
+    if (this.isLoading) {
+      let rect = new Rect(0, y, this.virtualizer.visibleRect.width, 40);
+      let loader = new LayoutInfo('loader', 'loader', rect);
+      let node = {
+        layoutInfo: loader,
+        validRect: loader.rect
+      };
+      nodes.push(node);
+      this.layoutNodes.set(loader.key, node);
+      y = loader.rect.maxY;
+    }
+
+    if (nodes.length === 0) {
+      let rect = new Rect(0, y, this.virtualizer.visibleRect.width, this.placeholderHeight ?? this.virtualizer.visibleRect.height);
+      let placeholder = new LayoutInfo('placeholder', 'placeholder', rect);
+      let node = {
+        layoutInfo: placeholder,
+        validRect: placeholder.rect
+      };
+      nodes.push(node);
+      this.layoutNodes.set(placeholder.key, node);
+      y = placeholder.rect.maxY;
+    }
+
+    this.contentSize.height = y + this.padding;
+    return nodes;
+  }
+
+  protected buildSection(node: Node<T>, x: number, y: number): LayoutNode {
+    // Synthesize a collection node for the header.
+    let headerNode = {
+      type: 'header',
+      key: node.key + ':header',
+      parentKey: node.key,
+      value: null,
+      level: node.level,
+      hasChildNodes: false,
+      childNodes: [],
+      rendered: node.rendered,
+      textValue: node.textValue
+    };
+
+    // Build layout node for it and adjust y offset of section children.
+    let header = this.buildSectionHeader(headerNode, x, y);
+    header.node = headerNode;
+    header.layoutInfo.parentKey = node.key;
+    this.layoutNodes.set(headerNode.key, header);
+    y += header.layoutInfo.rect.height;
+
+    let section = super.buildSection(node, x, y);
+    section.children.unshift(header);
+    return section;
+  }
+}