feat: show remote cursors when in collaboration.

apps/www/content/docs/collaboration.mdx

@@ -13,6 +13,8 @@ title: Collaboration
 ## Features
 
 - The yjs plugin enables support for collaboration using [slate-yjs](https://docs.slate-yjs.dev/) and [Hocuspocus](https://docs.slate-yjs.dev/walkthroughs/collaboration-hocuspocus).
+- By default remote cursors are not rendered unless you install the remote cursor overlay and include it in the config.
+- Cursors are rendered slightly faded and become solid on hover. Use the `data` field in `cursorOptions` to customise the display name and color.
 
 </PackageInfo>
 
@@ -28,22 +30,48 @@ npm install @udecode/plate-yjs
 
 ```tsx
 import { YjsPlugin } from '@udecode/plate-yjs/react';
+import { RemoteCursorOverlay } from '@/components/plate-ui/remote-cursor-overlay';
 
 const editor = createPlateEditor({
   plugins: [
     // ...otherPlugins,
     YjsPlugin.configure({
       options: {
+        render: {
+          afterEditable: RemoteCursorOverlay,
+        },
+        cursorOptions: {
+          autoSend: true,
+          data: { name: 'A plate user', color: '#5AC990' },
+        },
+        disableCursors: false,
         hocuspocusProviderOptions: {
-          url: "https://hocuspocus.test/hocuspocus",
-          name: "test",
+          url: 'https://hocuspocus.test/hocuspocus',
+          name: 'test',
         },
       },
     }),
   ],
 });
 ```
 
+### Editor Container
+
+The editor requires a container component above `PlateContent` to ensure correct cursor overlay positioning:
+
+```tsx
+export const EditorContainer = (
+  props: React.HTMLAttributes<HTMLDivElement>
+) => {
+  const editor = useEditorRef();
+  const containerRef = useEditorContainerRef();
+
+  return <div id={editor.uid} ref={containerRef} {...props} />;
+};
+```
+
+This component is available in [Editor](/docs/components/editor).
+
 ## Backend
 
 Follow the backend instructions in [Hocuspocus docs](https://tiptap.dev/hocuspocus/getting-started).

apps/www/public/r/index.json

@@ -1476,6 +1476,30 @@
     "registryDependencies": [],
     "type": "registry:ui"
   },
+  {
+    "dependencies": [
+      "@slate-yjs/react",
+      "@udecode/plate-core"
+    ],
+    "doc": {
+      "description": "A cursor overlay to display multiplayer cursors in the yjs plugin.",
+      "docs": [
+        {
+          "route": "/docs/collaboration"
+        }
+      ],
+      "examples": []
+    },
+    "files": [
+      {
+        "path": "plate-ui/remote-cursor-overlay.tsx",
+        "type": "registry:ui"
+      }
+    ],
+    "name": "remote-cursor-overlay",
+    "registryDependencies": [],
+    "type": "registry:ui"
+  },
   {
     "dependencies": [
       "@udecode/plate-ai",

apps/www/public/r/styles/default/remote-cursor-overlay.json

@@ -0,0 +1,26 @@
+{
+  "dependencies": [
+    "@slate-yjs/react",
+    "@udecode/plate-core"
+  ],
+  "doc": {
+    "description": "A cursor overlay to display multiplayer cursors in the yjs plugin.",
+    "docs": [
+      {
+        "route": "/docs/collaboration"
+      }
+    ],
+    "examples": []
+  },
+  "files": [
+    {
+      "content": "import React, {\n  type CSSProperties,\n  type PropsWithChildren,\n  useState,\n} from 'react';\n\nimport {\n  type CursorOverlayData,\n  useRemoteCursorOverlayPositions,\n} from '@slate-yjs/react';\nimport { useEditorContainerRef } from '@udecode/plate-core/react';\n\nexport function addAlpha(hexColor: string, opacity: number): string {\n  const normalized = Math.round(Math.min(Math.max(opacity, 0), 1) * 255);\n\n  return hexColor + normalized.toString(16).toUpperCase();\n}\n\nexport type CursorData = {\n  color: string;\n  name: string;\n};\n\ntype CaretProps = Pick<CursorOverlayData<CursorData>, 'caretPosition' | 'data'>;\nconst cursorOpacity = 0.7;\nconst hoverOpacity = 1;\n\nfunction Caret({ caretPosition, data }: CaretProps) {\n  const [isHover, setIsHover] = useState(false);\n\n  const handleMouseEnter = () => {\n    setIsHover(true);\n  };\n  const handleMouseLeave = () => {\n    setIsHover(false);\n  };\n  const caretStyle: CSSProperties = {\n    ...caretPosition,\n    background: data?.color,\n    opacity: cursorOpacity,\n    transition: 'opacity 0.2s',\n  };\n  const caretStyleHover = { ...caretStyle, opacity: hoverOpacity };\n\n  const labelStyle: CSSProperties = {\n    background: data?.color,\n    opacity: cursorOpacity,\n    transform: 'translateY(-100%)',\n    transition: 'opacity 0.2s',\n  };\n  const labelStyleHover = { ...labelStyle, opacity: hoverOpacity };\n\n  return (\n    <div\n      className=\"absolute w-0.5\"\n      style={isHover ? caretStyleHover : caretStyle}\n    >\n      <div\n        className=\"absolute top-0 whitespace-nowrap rounded rounded-bl-none px-1.5 py-0.5 text-xs text-white\"\n        style={isHover ? labelStyleHover : labelStyle}\n        onMouseEnter={handleMouseEnter}\n        onMouseLeave={handleMouseLeave}\n      >\n        {data?.name}\n      </div>\n    </div>\n  );\n}\n\nfunction RemoteSelection({\n  caretPosition,\n  data,\n  selectionRects,\n}: CursorOverlayData<CursorData>) {\n  if (!data) {\n    return null;\n  }\n\n  const selectionStyle: CSSProperties = {\n    // Add a opacity to the background color\n    backgroundColor: addAlpha(data.color, 0.5),\n  };\n\n  return (\n    <React.Fragment>\n      {selectionRects.map((position, i) => (\n        <div\n          key={i}\n          className=\"pointer-events-none absolute\"\n          style={{ ...selectionStyle, ...position }}\n        ></div>\n      ))}\n      {caretPosition && <Caret caretPosition={caretPosition} data={data} />}\n    </React.Fragment>\n  );\n}\n\ntype RemoteCursorsProps = PropsWithChildren<{\n  className?: string;\n}>;\n\nexport function RemoteCursorOverlay({ children }: RemoteCursorsProps) {\n  const containerRef = useEditorContainerRef();\n  const [cursors] = useRemoteCursorOverlayPositions<CursorData>({\n    containerRef,\n  });\n\n  return (\n    <>\n      {children}\n      {cursors.map((cursor) => (\n        <RemoteSelection key={cursor.clientId} {...cursor} />\n      ))}\n    </>\n  );\n}\n",
+      "path": "plate-ui/remote-cursor-overlay.tsx",
+      "target": "components/plate-ui/remote-cursor-overlay.tsx",
+      "type": "registry:ui"
+    }
+  ],
+  "name": "remote-cursor-overlay",
+  "registryDependencies": [],
+  "type": "registry:ui"
+}

apps/www/src/__registry__/index.tsx

@@ -877,6 +877,22 @@ export const Index: Record<string, any> = {
       subcategory: "",
       chunks: []
     },
+    "remote-cursor-overlay": {
+      name: "remote-cursor-overlay",
+      description: "",
+      type: "registry:ui",
+      registryDependencies: [],
+      files: [{
+        path: "src/registry/default/plate-ui/remote-cursor-overlay.tsx",
+        type: "registry:ui",
+        target: ""
+      }],
+      component: React.lazy(() => import("@/registry/default/plate-ui/remote-cursor-overlay.tsx")),
+      source: "",
+      category: "",
+      subcategory: "",
+      chunks: []
+    },
     "ai-menu": {
       name: "ai-menu",
       description: "",

apps/www/src/registry/default/plate-ui/remote-cursor-overlay.tsx

@@ -0,0 +1,109 @@
+// Lifted from slate-yjs https://github.com/BitPhinix/slate-yjs/blob/main/examples/frontend/src/pages/RemoteCursorOverlay/Overlay.tsx
+
+import React, { type CSSProperties, useState } from 'react';
+
+import {
+  type CursorOverlayData,
+  useRemoteCursorOverlayPositions,
+} from '@slate-yjs/react';
+import { useEditorContainerRef } from '@udecode/plate-core/react';
+
+export function addAlpha(hexColor: string, opacity: number): string {
+  const normalized = Math.round(Math.min(Math.max(opacity, 0), 1) * 255);
+
+  return hexColor + normalized.toString(16).toUpperCase();
+}
+
+export type CursorData = {
+  color: string;
+  name: string;
+};
+
+type CaretProps = Pick<CursorOverlayData<CursorData>, 'caretPosition' | 'data'>;
+const cursorOpacity = 0.7;
+const hoverOpacity = 1;
+
+function Caret({ caretPosition, data }: CaretProps) {
+  const [isHover, setIsHover] = useState(false);
+
+  const handleMouseEnter = () => {
+    setIsHover(true);
+  };
+  const handleMouseLeave = () => {
+    setIsHover(false);
+  };
+  const caretStyle: CSSProperties = {
+    ...caretPosition,
+    background: data?.color,
+    opacity: cursorOpacity,
+    transition: 'opacity 0.2s',
+  };
+  const caretStyleHover = { ...caretStyle, opacity: hoverOpacity };
+
+  const labelStyle: CSSProperties = {
+    background: data?.color,
+    opacity: cursorOpacity,
+    transform: 'translateY(-100%)',
+    transition: 'opacity 0.2s',
+  };
+  const labelStyleHover = { ...labelStyle, opacity: hoverOpacity };
+
+  return (
+    <div
+      className="absolute w-0.5"
+      style={isHover ? caretStyleHover : caretStyle}
+    >
+      <div
+        className="absolute top-0 whitespace-nowrap rounded rounded-bl-none px-1.5 py-0.5 text-xs text-white"
+        style={isHover ? labelStyleHover : labelStyle}
+        onMouseEnter={handleMouseEnter}
+        onMouseLeave={handleMouseLeave}
+      >
+        {data?.name}
+      </div>
+    </div>
+  );
+}
+
+function RemoteSelection({
+  caretPosition,
+  data,
+  selectionRects,
+}: CursorOverlayData<CursorData>) {
+  if (!data) {
+    return null;
+  }
+
+  const selectionStyle: CSSProperties = {
+    // Add a opacity to the background color
+    backgroundColor: addAlpha(data.color, 0.5),
+  };
+
+  return (
+    <React.Fragment>
+      {selectionRects.map((position, i) => (
+        <div
+          key={i}
+          className="pointer-events-none absolute"
+          style={{ ...selectionStyle, ...position }}
+        ></div>
+      ))}
+      {caretPosition && <Caret caretPosition={caretPosition} data={data} />}
+    </React.Fragment>
+  );
+}
+
+export function RemoteCursorOverlay() {
+  const containerRef = useEditorContainerRef();
+  const [cursors] = useRemoteCursorOverlayPositions<CursorData>({
+    containerRef,
+  });
+
+  return (
+    <>
+      {cursors.map((cursor) => (
+        <RemoteSelection key={cursor.clientId} {...cursor} />
+      ))}
+    </>
+  );
+}

apps/www/src/registry/registry-ui.ts

@@ -1723,6 +1723,21 @@ export const uiPrimitives: Registry = [
     registryDependencies: [],
     type: 'registry:ui',
   },
+  {
+    dependencies: ['@slate-yjs/react'],
+    doc: {
+      description:
+        'A cursor overlay to display multiplayer cursors in the yjs plugin.',
+      docs: [{ route: '/docs/collaboration' }],
+      examples: [],
+    },
+    files: [
+      { path: 'plate-ui/remote-cursor-overlay.tsx', type: 'registry:ui' },
+    ],
+    name: 'remote-cursor-overlay',
+    registryDependencies: [],
+    type: 'registry:ui',
+  },
 ];
 
 export const ui: Registry = [...uiNodes, ...uiPrimitives, ...uiComponents];

packages/yjs/src/react/YjsPlugin.tsx

@@ -5,5 +5,7 @@ import { YjsAboveEditable } from './YjsAboveEditable';
 
 /** Enables support for real-time collaboration using Yjs. */
 export const YjsPlugin = toPlatePlugin(BaseYjsPlugin, {
-  render: { aboveEditable: YjsAboveEditable },
+  render: {
+    aboveEditable: YjsAboveEditable,
+  },
 });