[General] [Fixed] - VirtualizedSectionList/SectionList: replace enableVirtualization prop annotation by correct underlying disableVirtualisation of VirtualizedList

Libraries/Lists/VirtualizedList.js

@@ -76,7 +76,7 @@ type OptionalProps = {
    * unmounts react instances that are outside of the render window. You should only need to disable
    * this for debugging purposes.
    */
-  disableVirtualization: boolean,
+  disableVirtualization?: ?boolean,
   /**
    * A marker property for telling the list to re-render (since it implements `PureComponent`). If
    * any of your `renderItem`, Header, Footer, etc. functions depend on anything outside of the
@@ -705,7 +705,7 @@ class VirtualizedList extends React.PureComponent<Props, State> {
   };
 
   _isVirtualizationDisabled(): boolean {
-    return this.props.disableVirtualization;
+    return this.props.disableVirtualization || false;
   }
 
   _isNestedWithSameOrientation(): boolean {

Libraries/Lists/VirtualizedSectionList.js

@@ -91,11 +91,11 @@ type OptionalProps<SectionT: SectionBase> = {
    */
   ItemSeparatorComponent?: ?React.ComponentType<any>,
   /**
-   * Warning: Virtualization can drastically improve memory consumption for long lists, but trashes
-   * the state of items when they scroll out of the render window, so make sure all relavent data is
-   * stored outside of the recursive `renderItem` instance tree.
+   * DEPRECATED: Virtualization provides significant performance and memory optimizations, but fully
+   * unmounts react instances that are outside of the render window. You should only need to disable
+   * this for debugging purposes.
    */
-  enableVirtualization?: ?boolean,
+  disableVirtualization?: ?boolean,
   keyExtractor: (item: Item, index: number) => string,
   onEndReached?: ?({distanceFromEnd: number}) => void,
   /**

RNTester/js/SectionListExample.js

@@ -149,7 +149,7 @@ class SectionListExample extends React.PureComponent<{}, $FlowFixMeState> {
           )}
           debug={this.state.debug}
           inverted={this.state.inverted}
-          enableVirtualization={this.state.virtualized}
+          disableVirtualization={!this.state.virtualized}
           onRefresh={() => Alert.alert('onRefresh: nothing to refresh :P')}
           onScroll={this._scrollSinkY}
           onViewableItemsChanged={this._onViewableItemsChanged}