warn about PureComponent in docs

Reviewed By: hramos

Differential Revision: D4663872

fbshipit-source-id: cb2bd2a2d588a9419da7517304d0612e259151e3

Libraries/CustomComponents/Lists/FlatList.js

@@ -179,12 +179,16 @@ type DefaultProps = typeof defaultProps;
  *
  * - Internal state is not preserved when content scrolls out of the render window. Make sure all
  *   your data is captured in the item data or external stores like Flux, Redux, or Relay.
+ * - This is a `PureComponent` which means that it will not re-render if `props` remain shallow-
+ *   equal. Make sure that everything your `renderItem` function depends on is passed as a prop that
+ *   is not `===` after updates, otherwise your UI may not update on changes. This includes the
+ *   `data` prop and parent component state.
  * - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
  *   offscreen. This means it's possible to scroll faster than the fill rate ands momentarily see
  *   blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
  *   and we are working on improving it behind the scenes.
  * - By default, the list looks for a `key` prop on each item and uses that for the React key.
- *   Alternatively, you can provide a custom keyExtractor prop.
+ *   Alternatively, you can provide a custom `keyExtractor` prop.
  */
 class FlatList<ItemT> extends React.PureComponent<DefaultProps, Props<ItemT>, void> {
   static defaultProps: DefaultProps = defaultProps;

Libraries/CustomComponents/Lists/SectionList.js

@@ -165,12 +165,16 @@ type DefaultProps = typeof VirtualizedSectionList.defaultProps;
  *
  * - Internal state is not preserved when content scrolls out of the render window. Make sure all
  *   your data is captured in the item data or external stores like Flux, Redux, or Relay.
+ * - This is a `PureComponent` which means that it will not re-render if `props` remain shallow-
+ *   equal. Make sure that everything your `renderItem` function depends on is passed as a prop that
+ *   is not `===` after updates, otherwise your UI may not update on changes. This includes the
+ *   `data` prop and parent component state.
  * - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
  *   offscreen. This means it's possible to scroll faster than the fill rate ands momentarily see
  *   blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
  *   and we are working on improving it behind the scenes.
  * - By default, the list looks for a `key` prop on each item and uses that for the React key.
- *   Alternatively, you can provide a custom keyExtractor prop.
+ *   Alternatively, you can provide a custom `keyExtractor` prop.
  */
 class SectionList<SectionT: SectionBase<any>>
   extends React.PureComponent<DefaultProps, Props<SectionT>, void>

Libraries/CustomComponents/Lists/VirtualizedList.js

@@ -163,12 +163,16 @@ type State = {first: number, last: number};
  *
  * - Internal state is not preserved when content scrolls out of the render window. Make sure all
  *   your data is captured in the item data or external stores like Flux, Redux, or Relay.
+ * - This is a `PureComponent` which means that it will not re-render if `props` remain shallow-
+ *   equal. Make sure that everything your `renderItem` function depends on is passed as a prop that
+ *   is not `===` after updates, otherwise your UI may not update on changes. This includes the
+ *   `data` prop and parent component state.
  * - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
  *   offscreen. This means it's possible to scroll faster than the fill rate ands momentarily see
  *   blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
  *   and we are working on improving it behind the scenes.
  * - By default, the list looks for a `key` prop on each item and uses that for the React key.
- *   Alternatively, you can provide a custom keyExtractor prop.
+ *   Alternatively, you can provide a custom `keyExtractor` prop.
  *
  * NOTE: `LayoutAnimation` and sticky section headers both have bugs when used with this and are
  * therefore not officially supported yet.