Fix issue with slate-react static ReactEditor.focus method

This will make sure we don't try to focus the editor while it's in the midst of applying operations.
If this is the case, retry setting focus in the next tick.

packages/slate-react/src/plugin/react-editor.ts

@@ -34,6 +34,7 @@ import {
   EDITOR_TO_SCHEDULE_FLUSH,
   EDITOR_TO_WINDOW,
   ELEMENT_TO_NODE,
+  FOCUS_TIMER_HANDLE,
   IS_COMPOSING,
   IS_FOCUSED,
   IS_READ_ONLY,
@@ -412,6 +413,25 @@ export const ReactEditor: ReactEditorInterface = {
   },
 
   focus: editor => {
+    // If the editor has pending operations, focus should be requested after
+    // those changes are applied. Retry in the next tick if this is the case.
+    if (editor.operations.length > 0) {
+      const handle = FOCUS_TIMER_HANDLE.get(editor)
+      if (handle) {
+        clearTimeout(handle)
+        FOCUS_TIMER_HANDLE.delete(editor)
+      }
+      FOCUS_TIMER_HANDLE.set(
+        editor,
+        setTimeout(() => {
+          // Flush changes before trying to focus again
+          editor.onChange()
+          ReactEditor.focus(editor)
+        })
+      )
+      return
+    }
+
     const el = ReactEditor.toDOMNode(editor, editor)
     const root = ReactEditor.findDocumentOrShadowRoot(editor)
     IS_FOCUSED.set(editor, true)

packages/slate-react/src/utils/weak-maps.ts

@@ -37,6 +37,7 @@ export const EDITOR_TO_KEY_TO_ELEMENT: WeakMap<
 export const IS_READ_ONLY: WeakMap<Editor, boolean> = new WeakMap()
 export const IS_FOCUSED: WeakMap<Editor, boolean> = new WeakMap()
 export const IS_COMPOSING: WeakMap<Editor, boolean> = new WeakMap()
+export const FOCUS_TIMER_HANDLE: WeakMap<Editor, NodeJS.Timeout> = new WeakMap()
 
 export const EDITOR_TO_USER_SELECTION: WeakMap<
   Editor,