feat(shared): display bookmark count on post cards

[nimrodkra]

Summary

• Add show_bookmark_count GrowthBook feature flag (default false)
• Add numBookmarks to Post interface and both FEED_POST_INFO_FRAGMENT / SHARED_POST_INFO_FRAGMENT GraphQL fragments
• Display InteractionCounter inside BookmarkButton in ActionButtons, gated by the feature flag
• Add optional bookmarks prop to PostEngagementCounts for the Similar Posts widget, also gated by the flag

Key decisions

• Feature flag evaluated independently in ActionButtons and SimilarPosts since they render in separate contexts
• PostEngagementCounts receives bookmarks as an optional prop threaded from the parent to avoid hooks in a static function component
• Separator rendering uses ternary instead of && to prevent React's falsy-number-rendering pitfall

Closes ENG-974

---

Created by Huginn 🐦‍⬛

Preview domain

https://eng-974-show-number-of-bookmarks.preview.app.daily.dev

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
daily-webapp	Ready	Preview	Mar 6, 2026 3:16am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
storybook	Ignored		Mar 6, 2026 3:16am

[nimrodkra]

Updated frontend to consume the analytics-based bookmark count from API.

What changed:

• switched bookmark count reads from post.numBookmarks to post.analytics.bookmarks
• updated shared GraphQL fragments/types accordingly
• kept feature flag gating behavior unchanged

Latest commit: 7774b0e.

[nimrodkra]

Found and fixed a likely CI lint failure cause: removed an unused Bookmark type import introduced during the optimistic bookmark count cache refactor (useBookmarkPost.ts).

Fix commit: 749b20b29.

[nimrodkra]

Quick demo:
https://github.com/user-attachments/assets/4ee11615-8452-4232-b42d-09b99c2a5dc2

[nimrodkra]

@claude please review this pr

[claude]

Claude finished @nimrodkra's task in 2m 2s —— View job

---

PR Review: feat(shared): display bookmark count on post cards

• Read all changed files
• Analyze code for bugs, correctness, and best practices
• Post review feedback

---

Overview

The implementation is generally clean and follows existing codebase patterns well. Feature flag gating is correctly applied, GraphQL fragments are updated appropriately, and the UI integration is consistent. A few issues worth calling out:

---

Issues

🔴 Rollback logic in defaultOnMutate is fragile

packages/shared/src/hooks/useBookmarkPost.ts lines 101–129:

const defaultOnMutate = ({ id }) => {
  updatePostCache(client, id, (post) => ({
    bookmarked: !post.bookmarked,
    analytics: post.analytics ? { ...post.analytics, bookmarks: getOptimisticBookmarkCount(...) } : post.analytics,
  }));

  return () => {
    // Rollback: re-reads current cache state and applies inverse
    updatePostCache(client, id, (post) => ({
      bookmarked: !post.bookmarked,
      analytics: post.analytics ? { ...post.analytics, bookmarks: getOptimisticBookmarkCount(...) } : post.analytics,
    }));
  };
};

This rollback works correctly by symmetry (applying the inverse transform produces the original values), but it doesn't capture the previous state. If any background refetch or concurrent update modifies post.analytics.bookmarks between the optimistic mutation and the rollback, the rollback will produce an incorrect result rather than restoring the original snapshot.

The mutateBookmarkFeedPost function does this correctly by capturing previousAnalytics explicitly before mutating. defaultOnMutate should do the same:

const defaultOnMutate = ({ id }) => {
  let previousAnalytics: Post['analytics'];
  let previousBookmarked: boolean | undefined;

  updatePostCache(client, id, (post) => {
    previousAnalytics = post.analytics;
    previousBookmarked = post.bookmarked;
    return {
      bookmarked: !post.bookmarked,
      analytics: post.analytics ? { ...post.analytics, bookmarks: getOptimisticBookmarkCount(...) } : post.analytics,
    };
  });

  return () => {
    updatePostCache(client, id, () => ({
      bookmarked: previousBookmarked,
      analytics: previousAnalytics,
    }));
  };
};

Fix this →

---

🟡 defaultOnMutate has an untyped parameter

packages/shared/src/hooks/useBookmarkPost.ts line 101:

const defaultOnMutate = ({ id }) => {

The { id } parameter is untyped. It should be typed as UseBookmarkPostMutationProps (which already exists):

const defaultOnMutate = ({ id }: UseBookmarkPostMutationProps) => {

Fix this →

---

🟡 analytics.impressions added to FEED_POST_INFO_FRAGMENT — was this intentional?

packages/shared/src/graphql/fragments.ts:

Both fragments now include analytics { impressions bookmarks }. If impressions wasn't previously fetched by FEED_POST_INFO_FRAGMENT (the main feed fragment), adding it increases payload size for every feed load. Worth confirming this is intentional and the impressions field is actually used elsewhere with FeedPostInfo, or trimming it to just bookmarks here.

---

Positives

• Separator logic in PostEngagementCounts correctly uses ternary (? ... : null) instead of && to prevent falsy-number rendering — good catch, mentioned in PR description.
• Feature flag pattern is consistent with other flags in the file; default false is appropriate for a new unreleased feature.
• Optimistic update in mutateBookmarkFeedPost correctly captures previousAnalytics and restores it on rollback.
• getOptimisticBookmarkCount helper correctly clamps at 0 with Math.max(0, ...) to prevent negative counts.
• PostEngagementCounts bookmark prop is optional and threaded correctly from SimilarPosts — keeps the component a pure function without hook dependencies.
• analytics type on Post is properly scoped as Partial<Pick<PostAnalytics, 'impressions' | 'bookmarks'>> rather than the full PostAnalytics type — matches what's actually fetched.

---

Summary

Two things to address before merging: the defaultOnMutate rollback fragility (minor in practice since concurrent mutations + rollbacks are rare, but correctness matters), and the untyped parameter. The impressions field question is low-priority but worth a quick sanity check.
| Branch

[nimrodkra]

Addressed Claude review in commit f6f231a.

Changes made:

• useBookmarkPost: defaultOnMutate now captures and restores an exact pre-mutation snapshot (bookmarked/bookmark/analytics) instead of relying on inverse symmetry during rollback.
• useBookmarkPost: added explicit typing to defaultOnMutate via NonNullable<UseBookmarkPostProps['onMutate']>.
• FEED_POST_INFO_FRAGMENT: removed analytics.impressions from this feed fragment to avoid unnecessary payload growth; it now requests only analytics.bookmarks for this feature.

This should resolve the two actionable findings and the fragment payload concern.