fix: add summary field in JSON output format (#20778)

* fix: add summary field in JSON output format

This fixes that the summary/description was not included in the feed.

As a side-note, we cannot remove the content_html field even if only the
summary/description is present.

> content_html and content_text are each optional strings — but one or
> both must be present.

* test: add JSON view tests

---------

lib/views/json.ts

@@ -19,8 +19,10 @@ const json = (data: Data) => {
             id: item.guid || item.id || item.link,
             url: item.link,
             title: item.title,
+            // content_html and content_text are each optional strings — but one or both must be present
             content_html: (item.content && item.content.html) || item.description || item.title,
             content_text: item.content && item.content.text,
+            summary: item.description,
             image: item.image || item.itunes_item_image,
             banner_image: item.banner,
             date_published: item.pubDate,

lib/views/views.test.tsx

@@ -139,6 +139,78 @@ describe('RSS view', () => {
     });
 });
 
+describe('JSON view', () => {
+    it('renders summary, authors, tags, attachments, and extras', () => {
+        const jsonOutput = jsonView({
+            title: 'JSON Feed',
+            link: 'https://example.com',
+            feedLink: 'https://example.com/feed.json',
+            description: 'JSON Description',
+            language: 'en',
+            author: 'Feed Author',
+            image: 'https://example.com/icon.png',
+            item: [
+                {
+                    title: 'Item One',
+                    link: 'https://example.com/one',
+                    description: 'Entry One',
+                    guid: 'guid-1',
+                    content: {
+                        html: '<p>hello</p>',
+                        text: 'hello',
+                    },
+                    image: 'https://example.com/image.jpg',
+                    banner: 'https://example.com/banner.jpg',
+                    pubDate: '2024-01-01T00:00:00Z',
+                    updated: '2024-01-02T00:00:00Z',
+                    author: 'Item Author',
+                    category: ['Tech', 'AI'],
+                    enclosure_url: 'https://example.com/audio.mp3',
+                    enclosure_type: 'audio/mpeg',
+                    enclosure_title: 'Audio Title',
+                    enclosure_length: 123,
+                    itunes_duration: 321,
+                    _extra: { foo: 'bar' },
+                },
+            ],
+        });
+
+        const feed = JSON.parse(jsonOutput);
+
+        expect(feed.version).toBe('https://jsonfeed.org/version/1.1');
+        expect(feed.title).toBe('JSON Feed');
+        expect(feed.home_page_url).toBe('https://example.com');
+        expect(feed.feed_url).toBe('https://example.com/feed.json');
+        expect(feed.description).toBe('JSON Description - Powered by RSSHub');
+        expect(feed.authors).toEqual([{ name: 'Feed Author' }]);
+        expect(feed.items).toHaveLength(1);
+        expect(feed.items[0]).toMatchObject({
+            id: 'guid-1',
+            url: 'https://example.com/one',
+            title: 'Item One',
+            content_html: '<p>hello</p>',
+            content_text: 'hello',
+            summary: 'Entry One',
+            image: 'https://example.com/image.jpg',
+            banner_image: 'https://example.com/banner.jpg',
+            date_published: '2024-01-01T00:00:00Z',
+            date_modified: '2024-01-02T00:00:00Z',
+            authors: [{ name: 'Item Author' }],
+            tags: ['Tech', 'AI'],
+            attachments: [
+                {
+                    url: 'https://example.com/audio.mp3',
+                    mime_type: 'audio/mpeg',
+                    title: 'Audio Title',
+                    size_in_bytes: 123,
+                    duration_in_seconds: 321,
+                },
+            ],
+        });
+        expect(feed.items[0]._extra).toEqual({ foo: 'bar' });
+    });
+});
+
 describe('Index view', () => {
     const renderIndex = async (debugInfo: string | undefined, debugQuery: string | undefined) => {
         const debugData = {