Move _latestEditorState assignment back to commit phase

Summary: Follow-up to D6994261. I believe this is more correct even though it is kind of a hacky approach.

Reviewed By: flarnie

Differential Revision: D7014753

fbshipit-source-id: 6107352ddbe5a90fa3235aae513a3c5b17574c55

src/component/base/DraftEditor.react.js

@@ -65,6 +65,60 @@ type State = {
 
 let didInitODS = false;
 
+class UpdateEditorState extends React.Component<{
+  editor: DraftEditor,
+  editorState: EditorState,
+}> {
+  render() {
+    return null;
+  }
+  componentDidMount() {
+    this._update();
+  }
+  componentDidUpdate() {
+    this._update();
+  }
+  _update() {
+    if (gkx('draft_js_remove_componentwillupdate')) {
+      /**
+       * Sometimes a render triggers a 'focus' or other event, and that will
+       * schedule a second render pass.
+       * In order to make sure the second render pass gets the latest editor
+       * state, we update it here.
+       * Example:
+       * render #1
+       * +
+       * |
+       * | cWU -> Nothing ... latestEditorState = STALE_STATE :(
+       * |
+       * | render -> this.props.editorState = FRESH_STATE
+       * | +         *and* set latestEditorState = FRESH_STATE
+       *   |
+       * | |
+       * | +--> triggers 'focus' event, calling 'handleFocus' with latestEditorState
+       * |                                                +
+       * |                                                |
+       * +>cdU -> latestEditorState = FRESH_STATE         | the 'handleFocus' call schedules render #2
+       *                                                  | with latestEditorState, which is FRESH_STATE
+       *                                                  |
+       * render #2 <--------------------------------------+
+       * +
+       * |
+       * | cwU -> nothing updates
+       * |
+       * | render -> this.props.editorState = FRESH_STATE which was passed in above
+       * |
+       * +>cdU fires and resets latestEditorState = FRESH_STATE
+       * ---
+       * Note that if we don't set latestEditorState in 'render' in the above
+       * diagram, then STALE_STATE gets passed to render #2.
+       */
+      const editor = this.props.editor;
+      editor._latestEditorState = this.props.editorState;
+    }
+  }
+}
+
 /**
  * `DraftEditor` is the root editor component. It composes a `contentEditable`
  * div, and provides a wide variety of useful function props for managing the
@@ -237,43 +291,6 @@ class DraftEditor extends React.Component<DraftEditorProps, State> {
   }
 
   render(): React.Node {
-    if (gkx('draft_js_remove_componentwillupdate')) {
-      /**
-       * Sometimes a render triggers a 'focus' or other event, and that will
-       * schedule a second render pass.
-       * In order to make sure the second render pass gets the latest editor
-       * state, we update it here.
-       * Example:
-       * render #1
-       * +
-       * |
-       * | cWU -> Nothing ... latestEditorState = STALE_STATE :(
-       * |
-       * | render -> this.props.editorState = FRESH_STATE
-       * | +         *and* set latestEditorState = FRESH_STATE
-       *   |
-       * | |
-       * | +--> triggers 'focus' event, calling 'handleFocus' with latestEditorState
-       * |                                                +
-       * |                                                |
-       * +>cdU -> latestEditorState = FRESH_STATE         | the 'handleFocus' call schedules render #2
-       *                                                  | with latestEditorState, which is FRESH_STATE
-       *                                                  |
-       * render #2 <--------------------------------------+
-       * +
-       * |
-       * | cwU -> nothing updates
-       * |
-       * | render -> this.props.editorState = FRESH_STATE which was passed in above
-       * |
-       * +>cdU fires and resets latestEditorState = FRESH_STATE
-       * ---
-       * Note that if we don't set latestEditorState in 'render' in the above
-       * diagram, then STALE_STATE gets passed to render #2.
-       */
-
-      this._latestEditorState = this.props.editorState;
-    }
     const {
       blockRenderMap,
       blockRendererFn,
@@ -381,6 +398,11 @@ class DraftEditor extends React.Component<DraftEditorProps, State> {
             style={contentStyle}
             suppressContentEditableWarning
             tabIndex={this.props.tabIndex}>
+            {/*
+              Needs to come earlier in the tree as a sibling (not ancestor) of
+              all DraftEditorLeaf nodes so it's first in postorder traversal.
+            */}
+            <UpdateEditorState editor={this} editorState={editorState} />
             <DraftEditorContents {...editorContentsProps} />
           </div>
         </div>