Fix rendering issues when both chunking and React's strict mode are enabled

.changeset/warm-months-hammer.md

@@ -0,0 +1,5 @@
+---
+'slate-react': patch
+---
+
+Fix rendering issues when both chunking and React's strict mode are enabled

packages/slate-react/src/chunking/reconcile-children.ts

@@ -31,8 +31,6 @@ export const reconcileChildren = (
     debug,
   }: ReconcileOptions
 ) => {
-  chunkTree.modifiedChunks.clear()
-
   const chunkTreeHelper = new ChunkTreeHelper(chunkTree, { chunkSize, debug })
   const childrenHelper = new ChildrenHelper(editor, children)
 

packages/slate-react/src/components/chunk-tree.tsx

@@ -1,4 +1,4 @@
-import React, { Fragment } from 'react'
+import React, { ComponentProps, Fragment, useEffect } from 'react'
 import { Element } from 'slate'
 import { Key } from 'slate-dom'
 import { RenderChunkProps } from './editable'
@@ -51,7 +51,17 @@ const ChunkAncestor = <C extends TChunkAncestor>(props: {
   })
 }
 
-const ChunkTree = ChunkAncestor<TChunkTree>
+const ChunkTree = (props: ComponentProps<typeof ChunkAncestor<TChunkTree>>) => {
+  // Clear the set of modified chunks only when React finishes rendering. The
+  // timing of this is important in strict mode because if the chunks are
+  // cleared during rendering (such as in reconcileChildren), strict mode's
+  // second render won't include them.
+  useEffect(() => {
+    props.root.modifiedChunks.clear()
+  })
+
+  return <ChunkAncestor {...props} />
+}
 
 const MemoizedChunk = React.memo(
   ChunkAncestor<TChunk>,

site/examples/js/huge-document.jsx

@@ -1,5 +1,5 @@
 import { faker } from '@faker-js/faker'
-import React, { useCallback, useEffect, useState } from 'react'
+import React, { StrictMode, useCallback, useEffect, useState } from 'react'
 import { createEditor as slateCreateEditor, Editor } from 'slate'
 import { Editable, Slate, withReact, useSelected } from 'slate-react'
 
@@ -41,6 +41,7 @@ const initialConfig = {
     'chunk'
   ),
   showSelectedHeadings: parseBoolean('selected_headings', false),
+  strictMode: parseBoolean('strict', false),
 }
 const setSearchParams = config => {
   if (searchParams) {
@@ -54,6 +55,7 @@ const setSearchParams = config => {
       'selected_headings',
       config.showSelectedHeadings ? 'true' : 'false'
     )
+    searchParams.set('strict', config.strictMode ? 'true' : 'false')
     history.replaceState({}, '', `?${searchParams.toString()}`)
   }
 }
@@ -129,6 +131,24 @@ const HugeDocumentExample = () => {
     ),
     [config.contentVisibilityMode, config.chunkOutlines]
   )
+  const editable = rendering ? (
+    <div>Rendering&hellip;</div>
+  ) : (
+    <Slate key={editorVersion} editor={editor} initialValue={initialValue}>
+      <Editable
+        placeholder="Enter some text…"
+        renderElement={renderElement}
+        renderChunk={config.chunkDivs ? renderChunk : undefined}
+        spellCheck
+        autoFocus
+      />
+    </Slate>
+  )
+  const editableWithStrictMode = config.strictMode ? (
+    <StrictMode>{editable}</StrictMode>
+  ) : (
+    editable
+  )
   return (
     <>
       <PerformanceControls
@@ -137,19 +157,7 @@ const HugeDocumentExample = () => {
         setConfig={setConfig}
       />
 
-      {rendering ? (
-        <div>Rendering&hellip;</div>
-      ) : (
-        <Slate key={editorVersion} editor={editor} initialValue={initialValue}>
-          <Editable
-            placeholder="Enter some text…"
-            renderElement={renderElement}
-            renderChunk={config.chunkDivs ? renderChunk : undefined}
-            spellCheck
-            autoFocus
-          />
-        </Slate>
-      )}
+      {editableWithStrictMode}
     </>
   )
 }
@@ -394,6 +402,21 @@ const PerformanceControls = ({ editor, config, setConfig }) => {
             Call <code>useSelected</code> in each heading
           </label>
         </p>
+
+        <p>
+          <label>
+            <input
+              type="checkbox"
+              checked={config.strictMode}
+              onChange={event =>
+                setConfig({
+                  strictMode: event.target.checked,
+                })
+              }
+            />{' '}
+            React strict mode (only works in localhost)
+          </label>
+        </p>
       </details>
 
       <details>

site/examples/js/richtext.jsx

@@ -194,10 +194,9 @@ const BlockButton = ({ format, icon }) => {
         format,
         isAlignType(format) ? 'align' : 'type'
       )}
-      onMouseDown={event => {
-        event.preventDefault()
-        toggleBlock(editor, format)
-      }}
+      onPointerDown={event => event.preventDefault()}
+      onClick={() => toggleBlock(editor, format)}
+      data-test-id={`block-button-${format}`}
     >
       <Icon>{icon}</Icon>
     </Button>
@@ -208,10 +207,8 @@ const MarkButton = ({ format, icon }) => {
   return (
     <Button
       active={isMarkActive(editor, format)}
-      onMouseDown={event => {
-        event.preventDefault()
-        toggleMark(editor, format)
-      }}
+      onPointerDown={event => event.preventDefault()}
+      onClick={() => toggleMark(editor, format)}
     >
       <Icon>{icon}</Icon>
     </Button>

site/examples/ts/huge-document.tsx

@@ -2,6 +2,7 @@ import { faker } from '@faker-js/faker'
 import React, {
   CSSProperties,
   Dispatch,
+  StrictMode,
   useCallback,
   useEffect,
   useState,
@@ -33,6 +34,7 @@ interface Config {
   chunkOutlines: boolean
   contentVisibilityMode: 'none' | 'element' | 'chunk'
   showSelectedHeadings: boolean
+  strictMode: boolean
 }
 
 const blocksOptions = [
@@ -78,6 +80,7 @@ const initialConfig: Config = {
     'chunk'
   ),
   showSelectedHeadings: parseBoolean('selected_headings', false),
+  strictMode: parseBoolean('strict', false),
 }
 
 const setSearchParams = (config: Config) => {
@@ -92,6 +95,7 @@ const setSearchParams = (config: Config) => {
       'selected_headings',
       config.showSelectedHeadings ? 'true' : 'false'
     )
+    searchParams.set('strict', config.strictMode ? 'true' : 'false')
     history.replaceState({}, '', `?${searchParams.toString()}`)
   }
 }
@@ -183,6 +187,26 @@ const HugeDocumentExample = () => {
     [config.contentVisibilityMode, config.chunkOutlines]
   )
 
+  const editable = rendering ? (
+    <div>Rendering&hellip;</div>
+  ) : (
+    <Slate key={editorVersion} editor={editor} initialValue={initialValue}>
+      <Editable
+        placeholder="Enter some text…"
+        renderElement={renderElement}
+        renderChunk={config.chunkDivs ? renderChunk : undefined}
+        spellCheck
+        autoFocus
+      />
+    </Slate>
+  )
+
+  const editableWithStrictMode = config.strictMode ? (
+    <StrictMode>{editable}</StrictMode>
+  ) : (
+    editable
+  )
+
   return (
     <>
       <PerformanceControls
@@ -191,19 +215,7 @@ const HugeDocumentExample = () => {
         setConfig={setConfig}
       />
 
-      {rendering ? (
-        <div>Rendering&hellip;</div>
-      ) : (
-        <Slate key={editorVersion} editor={editor} initialValue={initialValue}>
-          <Editable
-            placeholder="Enter some text…"
-            renderElement={renderElement}
-            renderChunk={config.chunkDivs ? renderChunk : undefined}
-            spellCheck
-            autoFocus
-          />
-        </Slate>
-      )}
+      {editableWithStrictMode}
     </>
   )
 }
@@ -483,6 +495,21 @@ const PerformanceControls = ({
             Call <code>useSelected</code> in each heading
           </label>
         </p>
+
+        <p>
+          <label>
+            <input
+              type="checkbox"
+              checked={config.strictMode}
+              onChange={event =>
+                setConfig({
+                  strictMode: event.target.checked,
+                })
+              }
+            />{' '}
+            React strict mode (only works in localhost)
+          </label>
+        </p>
       </details>
 
       <details>