Fix types + documentation for CellRendererComponent

Summary:
CellRendererComponent can be given a more useful description, and more constrained type, to ensure it is used more correctly.

Changelog:
[General][Fixed] - Fix types + documentation for CellRendererComponent

Reviewed By: yungsters

Differential Revision: D43925572

fbshipit-source-id: 26aae6a2df989993c97709ffbf1544df7cbae036

packages/virtualized-lists/Lists/VirtualizedList.d.ts

@@ -87,6 +87,16 @@ export type ListRenderItem<ItemT> = (
   info: ListRenderItemInfo<ItemT>,
 ) => React.ReactElement | null;
 
+export interface CellRendererProps<ItemT> {
+  cellKey: string;
+  children: React.ReactNode;
+  index: number;
+  item: ItemT;
+  onFocusCapture?: ((event: FocusEvent) => void) | undefined;
+  onLayout?: ((event: LayoutChangeEvent) => void) | undefined;
+  style: StyleProp<ViewStyle> | undefined;
+}
+
 /**
  * @see https://reactnative.dev/docs/virtualizedlist
  */
@@ -370,5 +380,14 @@ export interface VirtualizedListWithoutRenderItemProps<ItemT>
    */
   windowSize?: number | undefined;
 
-  CellRendererComponent?: React.ComponentType<any> | undefined;
+  /**
+   * CellRendererComponent allows customizing how cells rendered by
+   * `renderItem`/`ListItemComponent` are wrapped when placed into the
+   * underlying ScrollView. This component must accept event handlers which
+   * notify VirtualizedList of changes within the cell.
+   */
+  CellRendererComponent?:
+    | React.ComponentType<CellRendererProps<ItemT>>
+    | null
+    | undefined;
 }

packages/virtualized-lists/Lists/VirtualizedList.js

@@ -748,29 +748,31 @@ class VirtualizedList extends StateSafePureComponent<Props, State> {
     const end = getItemCount(data) - 1;
     let prevCellKey;
     last = Math.min(end, last);
+
     for (let ii = first; ii <= last; ii++) {
       const item = getItem(data, ii);
       const key = this._keyExtractor(item, ii, this.props);
+
       this._indicesToKeys.set(ii, key);
       if (stickyIndicesFromProps.has(ii + stickyOffset)) {
         stickyHeaderIndices.push(cells.length);
       }
+
+      const shouldListenForLayout =
+        getItemLayout == null || debug || this._fillRateHelper.enabled();
+
       cells.push(
         <CellRenderer
           CellRendererComponent={CellRendererComponent}
           ItemSeparatorComponent={ii < end ? ItemSeparatorComponent : undefined}
           ListItemComponent={ListItemComponent}
           cellKey={key}
-          debug={debug}
-          fillRateHelper={this._fillRateHelper}
-          getItemLayout={getItemLayout}
           horizontal={horizontal}
           index={ii}
           inversionStyle={inversionStyle}
           item={item}
           key={key}
           prevCellKey={prevCellKey}
-          onCellLayout={this._onCellLayout}
           onUpdateSeparators={this._onUpdateSeparators}
           onCellFocusCapture={e => this._onCellFocusCapture(key)}
           onUnmount={this._onCellUnmount}
@@ -778,6 +780,9 @@ class VirtualizedList extends StateSafePureComponent<Props, State> {
             this._cellRefs[key] = ref;
           }}
           renderItem={renderItem}
+          {...(shouldListenForLayout && {
+            onCellLayout: this._onCellLayout,
+          })}
         />,
       );
       prevCellKey = key;

packages/virtualized-lists/Lists/VirtualizedListCellRenderer.js

@@ -13,8 +13,7 @@ import type {
   FocusEvent,
   LayoutEvent,
 } from 'react-native/Libraries/Types/CoreEventTypes';
-import type FillRateHelper from './FillRateHelper';
-import type {RenderItemType} from './VirtualizedListProps';
+import type {CellRendererProps, RenderItemType} from './VirtualizedListProps';
 
 import {View, StyleSheet} from 'react-native';
 import {VirtualizedListCellContextProvider} from './VirtualizedListContext.js';
@@ -22,28 +21,17 @@ import invariant from 'invariant';
 import * as React from 'react';
 
 export type Props<ItemT> = {
-  CellRendererComponent?: ?React.ComponentType<any>,
+  CellRendererComponent?: ?React.ComponentType<CellRendererProps<ItemT>>,
   ItemSeparatorComponent: ?React.ComponentType<
     any | {highlighted: boolean, leadingItem: ?ItemT},
   >,
   ListItemComponent?: ?(React.ComponentType<any> | React.Element<any>),
   cellKey: string,
-  debug?: ?boolean,
-  fillRateHelper: FillRateHelper,
-  getItemLayout?: (
-    data: any,
-    index: number,
-  ) => {
-    length: number,
-    offset: number,
-    index: number,
-    ...
-  },
   horizontal: ?boolean,
   index: number,
   inversionStyle: ViewStyleProp,
   item: ItemT,
-  onCellLayout: (event: LayoutEvent, cellKey: string, index: number) => void,
+  onCellLayout?: (event: LayoutEvent, cellKey: string, index: number) => void,
   onCellFocusCapture?: (event: FocusEvent) => void,
   onUnmount: (cellKey: string) => void,
   onUpdateSeparators: (
@@ -181,14 +169,13 @@ export default class CellRenderer<ItemT> extends React.Component<
       CellRendererComponent,
       ItemSeparatorComponent,
       ListItemComponent,
-      debug,
-      fillRateHelper,
-      getItemLayout,
+      cellKey,
       horizontal,
       item,
       index,
       inversionStyle,
       onCellFocusCapture,
+      onCellLayout,
       renderItem,
     } = this.props;
     const element = this._renderElement(
@@ -198,11 +185,6 @@ export default class CellRenderer<ItemT> extends React.Component<
       index,
     );
 
-    const onLayout =
-      (getItemLayout && !debug && !fillRateHelper.enabled()) ||
-      !this.props.onCellLayout
-        ? undefined
-        : this._onLayout;
     // NOTE: that when this is a sticky header, `onLayout` will get automatically extracted and
     // called explicitly by `ScrollViewStickyHeader`.
     const itemSeparator: React.Node = React.isValidElement(
@@ -224,21 +206,19 @@ export default class CellRenderer<ItemT> extends React.Component<
     const result = !CellRendererComponent ? (
       <View
         style={cellStyle}
-        onLayout={onLayout}
         onFocusCapture={onCellFocusCapture}
-        /* $FlowFixMe[incompatible-type-arg] (>=0.89.0 site=react_native_fb) *
-        This comment suppresses an error found when Flow v0.89 was deployed. *
-        To see the error, delete this comment and run Flow. */
-      >
+        {...(onCellLayout && {onLayout: this._onLayout})}>
         {element}
         {itemSeparator}
       </View>
     ) : (
       <CellRendererComponent
-        {...this.props}
+        cellKey={cellKey}
+        index={index}
+        item={item}
         style={cellStyle}
-        onLayout={onLayout}
-        onFocusCapture={onCellFocusCapture}>
+        onFocusCapture={onCellFocusCapture}
+        {...(onCellLayout && {onLayout: this._onLayout})}>
         {element}
         {itemSeparator}
       </CellRendererComponent>

packages/virtualized-lists/Lists/VirtualizedListProps.js

@@ -9,6 +9,10 @@
  */
 
 import {typeof ScrollView} from 'react-native';
+import type {
+  FocusEvent,
+  LayoutEvent,
+} from 'react-native/Libraries/Types/CoreEventTypes';
 import type {ViewStyleProp} from 'react-native/Libraries/StyleSheet/StyleSheet';
 import type {
   ViewabilityConfig,
@@ -34,6 +38,16 @@ export type RenderItemProps<ItemT> = {
   ...
 };
 
+export type CellRendererProps<ItemT> = $ReadOnly<{
+  cellKey: string,
+  children: React.Node,
+  index: number,
+  item: ItemT,
+  onFocusCapture?: (event: FocusEvent) => void,
+  onLayout?: (event: LayoutEvent) => void,
+  style: ViewStyleProp,
+}>;
+
 export type RenderItemType<ItemT> = (
   info: RenderItemProps<ItemT>,
 ) => React.Node;
@@ -102,10 +116,12 @@ type OptionalProps = {|
   inverted?: ?boolean,
   keyExtractor?: ?(item: Item, index: number) => string,
   /**
-   * Each cell is rendered using this element. Can be a React Component Class,
-   * or a render function. Defaults to using View.
+   * CellRendererComponent allows customizing how cells rendered by
+   * `renderItem`/`ListItemComponent` are wrapped when placed into the
+   * underlying ScrollView. This component must accept event handlers which
+   * notify VirtualizedList of changes within the cell.
    */
-  CellRendererComponent?: ?React.ComponentType<any>,
+  CellRendererComponent?: ?React.ComponentType<CellRendererProps<Item>>,
   /**
    * Rendered in between each item, but not at the top or bottom. By default, `highlighted` and
    * `leadingItem` props are provided. `renderItem` provides `separators.highlight`/`unhighlight`

packages/virtualized-lists/index.js

@@ -24,6 +24,7 @@ export type {
   ViewabilityConfigCallbackPair,
 } from './Lists/ViewabilityHelper';
 export type {
+  CellRendererProps,
   RenderItemProps,
   RenderItemType,
   Separators,