[Docs] Update with-slate example (#39639)

## Changelog

- Migrated `with-slate` example to typescript
- Updated dependencies to latest stable versions
- Added api route to demonstrate saving of `editorState`

## Documentation / Examples

- [x] Make sure the linting passes by running `pnpm lint`
- [x] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)

examples/with-slate/package.json

@@ -7,10 +7,15 @@
   },
   "dependencies": {
     "next": "latest",
-    "react": "^18.0.0",
-    "react-dom": "^18.0.0",
-    "slate": "^0.76.1",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "slate": "^0.82.0",
     "slate-history": "0.66.0",
-    "slate-react": "^0.76.1"
+    "slate-react": "^0.82.0"
+  },
+  "devDependencies": {
+    "@types/node": "18.7.5",
+    "@types/react": "18.0.17",
+    "typescript": "4.7.4"
   }
 }

examples/with-slate/pages/api/editor-state.ts

@@ -0,0 +1,20 @@
+import { NextApiRequest, NextApiResponse } from 'next'
+
+export default async function handleEditorStateChange(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  if (req.method !== 'POST') {
+    return res
+      .setHeader('Allow', ['POST'])
+      .status(405)
+      .end(`Method ${req.method} Not Allowed`)
+  }
+
+  const editorState = JSON.parse(req.body)
+  console.log('TODO: Save editorState on the server', editorState)
+
+  res.json({
+    status: 'ok',
+  })
+}

examples/with-slate/pages/index.tsx

@@ -0,0 +1,51 @@
+import { useState } from 'react'
+import { createEditor, Descendant } from 'slate'
+import { Slate, Editable, withReact } from 'slate-react'
+import { withHistory } from 'slate-history'
+import { InferGetServerSidePropsType } from 'next'
+
+export async function getServerSideProps() {
+  return {
+    props: {
+      editorState: [
+        {
+          children: [
+            { text: 'This is editable plain text, just like a <textarea>!' },
+          ],
+        },
+      ],
+    },
+  }
+}
+
+async function saveEditorState(edtorState: Descendant[]) {
+  const response = await fetch('/api/editor-state', {
+    method: 'POST',
+    body: JSON.stringify(edtorState),
+  })
+  return response.json()
+}
+
+export default function IndexPage({
+  editorState,
+}: InferGetServerSidePropsType<typeof getServerSideProps>) {
+  const [editor] = useState(() => withReact(withHistory(createEditor())))
+  return (
+    <Slate
+      editor={editor}
+      value={editorState}
+      onChange={async (value) => {
+        const isAstChange = editor.operations.some(
+          (op) => 'set_selection' !== op.type
+        )
+        if (isAstChange) {
+          // You might want to debounce the following call!
+          const responseData = await saveEditorState(value)
+          console.log('Send editor state to the server', responseData)
+        }
+      }}
+    >
+      <Editable placeholder="Enter some plain text..." />
+    </Slate>
+  )
+}

examples/with-slate/tsconfig.json

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "noEmit": true,
+    "incremental": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve"
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
+  "exclude": ["node_modules"]
+}

examples/with-slate/types/slate.d.ts

@@ -0,0 +1,14 @@
+import { BaseEditor } from 'slate'
+import { ReactEditor } from 'slate-react'
+import { HistoryEditor } from 'slate-history'
+
+type CustomElement = { type?: 'paragraph'; children: CustomText[] }
+type CustomText = { text: string; bold?: true }
+
+declare module 'slate' {
+  interface CustomTypes {
+    Editor: BaseEditor & ReactEditor & HistoryEditor
+    Element: CustomElement
+    Text: CustomText
+  }
+}