fix(core): error boundary should allow no children

packages/docusaurus-module-type-aliases/src/index.d.ts

@@ -88,7 +88,7 @@ declare module '@theme/Layout' {
   import type {ReactNode} from 'react';
 
   export interface Props {
-    readonly children: ReactNode;
+    readonly children?: ReactNode;
     readonly title?: string;
     readonly description?: string;
   }

packages/docusaurus-theme-classic/src/theme-classic.d.ts

@@ -221,7 +221,7 @@ declare module '@theme/Layout' {
   import type {ReactNode} from 'react';
 
   export interface Props {
-    readonly children: ReactNode;
+    readonly children?: ReactNode;
     readonly title?: string;
     readonly noFooter?: boolean;
     readonly description?: string;

packages/docusaurus/src/client/exports/ErrorBoundary.tsx

@@ -40,7 +40,11 @@ class ErrorBoundary extends React.Component<Props, State> {
       });
     }
 
-    return children;
+    return (
+      children ??
+      // See https://github.com/facebook/docusaurus/issues/6337#issuecomment-1012913647
+      null
+    );
   }
 }
 

website/_dogfooding/_pages tests/layout-no-children.tsx

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import React from 'react';
+import Layout from '@theme/Layout';
+
+// See https://github.com/facebook/docusaurus/issues/6337#issuecomment-1012913647
+export default function LayoutNoChildren(): JSX.Element {
+  return <Layout />;
+}