Show updated date on blog post cards

[vanrensbird]

What

Renders an Updated {date} label on blog post cards alongside the original publish date, separated by a | when both are present.

Threads an optional updatedAt field (already defined in source.config.ts as z.coerce.date().optional()) from post frontmatter through the card builders to the shared PostCard UI component:

• packages/ui/src/components/post-card.tsx — adds updatedAt to the type and renders the label + | separator (aria-hidden, only shown when both dates exist)
• apps/blog/src/components/PostCard.tsx — passes a formatted updatedAt through
• apps/blog/src/components/BlogGrid.tsx — adds updatedAt to BlogCardItem
• apps/blog/src/lib/post-card-item.ts, apps/blog/src/app/(blog)/page.tsx, apps/blog/src/app/(blog)/series/[key]/page.tsx — each compute updatedAtISO from frontmatter with NaN guards

Why

Surfaces refresh dates on the series and home listings, supporting the blog-refresh program's ability to tie content updates to visitor changes.

Testing

• tsc --noEmit passes clean
• Verified in dev server: the 4 refreshed backend-TS series posts render <original date> | Updated July 3, 2026; posts without updatedAt show no label

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Posts can now display an “Updated” date when a valid last-updated timestamp is available.
  • Blog cards and post cards now carry updated-date information throughout the app.
• Bug Fixes
  • Invalid or missing updated-date values are now handled safely and won’t break post displays.
  • When both publish and update dates exist, they are shown together with clear separation.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
blog	Ready	Preview, Comment	Jul 6, 2026 11:28am
docs	Ready	Preview, Comment	Jul 6, 2026 11:28am
eclipse	Ready	Preview, Comment	Jul 6, 2026 11:28am
site	Ready	Preview, Comment	Jul 6, 2026 11:28am

[coderabbitai]

Walkthrough

Adds an optional updatedAt field to blog post data flows. Parses and validates updatedAt timestamps in the blog home, series, and post-card-item builders, extends BlogCardItem/PostCardItem types across blog and UI packages, and renders an "Updated" label with separator in the shared PostCard component.

Changes

updatedAt Propagation

Layer / File(s)	Summary
Type contracts apps/blog/src/components/BlogGrid.tsx, apps/blog/src/components/PostCard.tsx, packages/ui/src/components/post-card.tsx	Adds optional updatedAt?: string | null to BlogCardItem and PostCardItem type declarations.
Parsing and mapping updatedAt apps/blog/src/app/(blog)/page.tsx, apps/blog/src/app/(blog)/series/[key]/page.tsx, apps/blog/src/lib/post-card-item.ts, apps/blog/src/components/PostCard.tsx	Validates and converts data.updatedAt/post.updatedAt into an ISO string (falling back to null) and includes it in returned card items.
Rendering updatedAt packages/ui/src/components/post-card.tsx	Renders "Updated {updatedAt}" with a conditional separator when both date and updatedAt are present.

Estimated code review effort: 2 (Simple) | ~12 minutes

Possibly related PRs

• prisma/web#7970: Both PRs implement the same updatedAt blog-post field—this PR propagates it through card types and rendering while the related PR extends the schema and uses it on the slug page's "Updated…"/dateModified output.

Poem

A field named updatedAt hops in,
Through pages, cards, and props within,
Validated dates, ISO-bound,
A tiny pipe separator found,
"Updated" now the readers grin. 🐰

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: surfacing updated dates on blog post cards.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[argos-ci]

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	Jul 6, 2026, 11:35 AM

[coderabbitai]

🧹 Nitpick comments (1)

apps/blog/src/app/(blog)/page.tsx (1)

93-99: 📐 Maintainability & Code Quality | 🔵 Trivial | 💤 Low value

Minor inconsistency: unlike dateISO above, this block skips the try/catch.

The dateISO computation just above wraps new Date(data.date) in try/catch; this new updatedAtISO block doesn't, despite parsing similarly untrusted frontmatter data. Low risk since new Date() rarely throws for string/Date inputs, but worth aligning for consistency.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@apps/blog/src/app/`(blog)/page.tsx around lines 93 - 99, The updatedAtISO
parsing block in page.tsx is inconsistent with the dateISO logic because it does
not use the same try/catch pattern around untrusted frontmatter parsing. Update
the updatedAtISO computation in the same render/data-prep flow as dateISO to
mirror that error-handling style, using the existing data.updatedAt handling and
keeping the fallback to null if parsing fails.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@apps/blog/src/app/`(blog)/page.tsx:
- Around line 93-99: The updatedAtISO parsing block in page.tsx is inconsistent
with the dateISO logic because it does not use the same try/catch pattern around
untrusted frontmatter parsing. Update the updatedAtISO computation in the same
render/data-prep flow as dateISO to mirror that error-handling style, using the
existing data.updatedAt handling and keeping the fallback to null if parsing
fails.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: e89e48e7-646d-465f-9f0e-18efc53c7127

📥 Commits

Reviewing files that changed from the base of the PR and between 4ce472a and e15884a.

📒 Files selected for processing (6)

• apps/blog/src/app/(blog)/page.tsx
• apps/blog/src/app/(blog)/series/[key]/page.tsx
• apps/blog/src/components/BlogGrid.tsx
• apps/blog/src/components/PostCard.tsx
• apps/blog/src/lib/post-card-item.ts
• packages/ui/src/components/post-card.tsx