fix: following pagination returns cursor and errors (#33) (thanks @VACInc)

CHANGELOG.md

@@ -22,6 +22,7 @@
 - Tweet JSON output now includes media items (photos, videos, GIFs) (#14) — thanks @Hormold
 - Bookmarks can resume pagination from a cursor (#26) — thanks @leonho
 - `unbookmark` command to remove bookmarked tweets (#22) — thanks @mbelinky.
+- `following` now paginates with cursors and surfaces partial-page errors (#33) — thanks @VACInc.
 
 ### Changed
 - Feature flags can be overridden at runtime via `features.json` (refreshable via `query-ids`).

tests/twitter-client.following-pagination.test.ts

@@ -0,0 +1,153 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { TwitterClient } from '../src/lib/twitter-client.js';
+import type { TwitterClientPrivate } from './twitter-client-fixtures.js';
+import { validCookies } from './twitter-client-fixtures.js';
+
+const originalFetch = global.fetch;
+
+const makeUserEntry = (id: string, username: string, name: string) => ({
+  content: {
+    itemContent: {
+      user_results: {
+        result: {
+          __typename: 'User',
+          rest_id: id,
+          legacy: {
+            screen_name: username,
+            name,
+            followers_count: 10,
+            friends_count: 5,
+            profile_image_url_https: 'https://img/test_normal.jpg',
+          },
+          is_blue_verified: false,
+          core: {
+            screen_name: username,
+            name,
+          },
+        },
+      },
+    },
+  },
+});
+
+describe('TwitterClient following pagination', () => {
+  let mockFetch: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    mockFetch = vi.fn();
+    global.fetch = mockFetch as unknown as typeof fetch;
+  });
+
+  afterEach(() => {
+    global.fetch = originalFetch;
+    vi.restoreAllMocks();
+  });
+
+  it('paginates following results with cursor', async () => {
+    mockFetch
+      .mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        json: async () => ({
+          data: {
+            user: {
+              result: {
+                timeline: {
+                  timeline: {
+                    instructions: [
+                      {
+                        entries: [
+                          makeUserEntry('1', 'alice', 'Alice'),
+                          { content: { cursorType: 'Bottom', value: 'cursor-2' } },
+                        ],
+                      },
+                    ],
+                  },
+                },
+              },
+            },
+          },
+        }),
+      })
+      .mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        json: async () => ({
+          data: {
+            user: {
+              result: {
+                timeline: {
+                  timeline: {
+                    instructions: [
+                      {
+                        entries: [makeUserEntry('2', 'bob', 'Bob')],
+                      },
+                    ],
+                  },
+                },
+              },
+            },
+          },
+        }),
+      });
+
+    const client = new TwitterClient({ cookies: validCookies });
+    const clientPrivate = client as unknown as TwitterClientPrivate;
+    clientPrivate.getFollowingQueryIds = async () => ['q1'];
+    clientPrivate.getFollowingViaRest = vi.fn();
+
+    const result = await client.getFollowing('user-id', 3);
+
+    expect(result.success).toBe(true);
+    expect(result.users).toHaveLength(2);
+    expect(result.users?.[0].username).toBe('alice');
+    expect(result.users?.[1].username).toBe('bob');
+    expect(result.nextCursor).toBeUndefined();
+    expect(mockFetch).toHaveBeenCalledTimes(2);
+  });
+
+  it('returns error when a later page fails', async () => {
+    mockFetch
+      .mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        json: async () => ({
+          data: {
+            user: {
+              result: {
+                timeline: {
+                  timeline: {
+                    instructions: [
+                      {
+                        entries: [
+                          makeUserEntry('1', 'alice', 'Alice'),
+                          { content: { cursorType: 'Bottom', value: 'cursor-2' } },
+                        ],
+                      },
+                    ],
+                  },
+                },
+              },
+            },
+          },
+        }),
+      })
+      .mockResolvedValueOnce({
+        ok: false,
+        status: 500,
+        text: async () => 'boom',
+      });
+
+    const client = new TwitterClient({ cookies: validCookies });
+    const clientPrivate = client as unknown as TwitterClientPrivate;
+    clientPrivate.getFollowingQueryIds = async () => ['q1'];
+    clientPrivate.getFollowingViaRest = vi.fn().mockResolvedValue({ success: false, error: 'rest fail' });
+
+    const result = await client.getFollowing('user-id', 3);
+
+    expect(result.success).toBe(false);
+    expect(result.users).toHaveLength(1);
+    expect(result.error).toContain('500');
+    expect(result.nextCursor).toBe('cursor-2');
+  });
+});