fix(portal): render an operation whose response example has no value

portal-template/src/components/api-page.tsx

@@ -1,11 +1,13 @@
 import { createOpenAPIPage } from 'fumadocs-openapi/ui';
 import { createCodeUsageGeneratorRegistry } from 'fumadocs-openapi/requests/generators';
+import { CodeBlock } from './code-block';
 import { renderExampleLayout } from './example-layout';
 import { renderUsageTabs } from './usage-tabs';
 
 export const OpenAPIPage = createOpenAPIPage({
   // Without a registry of its own, Fumadocs registers and bundles every request generator it has.
   codeUsages: createCodeUsageGeneratorRegistry(),
   generateTypeScriptDefinitions: false,
+  components: { CodeBlock },
   content: { renderAPIExampleLayout: renderExampleLayout, renderAPIExampleUsageTabs: renderUsageTabs }
 });

portal-template/src/components/code-block.tsx

@@ -0,0 +1,9 @@
+import { DynamicCodeBlock } from 'fumadocs-ui/components/dynamic-codeblock.core';
+import { useRenderContext } from 'fumadocs-openapi/ui';
+
+// Fumadocs passes `JSON.stringify(example.value)`, which is undefined for an example with no `value`.
+export function CodeBlock({ lang, code }: Readonly<{ lang: string; code: string | undefined }>) {
+  const { shiki, shikiOptions } = useRenderContext();
+  if (code === undefined) return null;
+  return <DynamicCodeBlock lang={lang} code={code} highlighter={() => shiki.getOrInit()} options={shikiOptions} />;
+}

portal-template/src/components/usage-tabs.tsx

@@ -1,11 +1,11 @@
 import { useEffect, useState, type ReactNode } from 'react';
 import { CodeBlockTab, CodeBlockTabs, CodeBlockTabsList, CodeBlockTabsTrigger } from 'fumadocs-ui/components/codeblock';
-import { DynamicCodeBlock } from 'fumadocs-ui/components/dynamic-codeblock.core';
 import { useOperationContext, useRenderContext, useServerContext } from 'fumadocs-openapi/ui';
 import { pathnameFromRequest } from 'fumadocs-openapi/requests/generators';
 import { curl } from 'fumadocs-openapi/requests/generators/curl';
 import { joinURL, resolveServerUrl } from '@fumadocs/api-docs/utils/url';
 import { CodeSample } from '@/lib/code-samples';
+import { CodeBlock } from './code-block';
 import { useExampleSelection } from './example-layout';
 
 interface UsageTab {
@@ -68,11 +68,6 @@ function CurlCode() {
   return <CodeBlock lang={curl.lang} code={curl.generate({ ...request, url }, { mediaAdapters, custom: null })} />;
 }
 
-function CodeBlock({ lang, code }: Readonly<{ lang: string; code: string }>) {
-  const { shiki, shikiOptions } = useRenderContext();
-  return <DynamicCodeBlock lang={lang} code={code} highlighter={() => shiki.getOrInit()} options={shikiOptions} />;
-}
-
 // Fumadocs reports the playground's edits to the selected example through its listeners.
 function useSelectedRequest() {
   const { examples, example, addListener, removeListener } = useOperationContext();