React Best Practices Review (Performance-First)

Use this skill to turn “React feels slow / Next.js page is heavy / too many requests” into a repeatable, prioritized review.

This skill is intentionally built like a rule library:

• SKILL.md: how to review + how to search rules
• references/rules/*: one rule per file (taggable, sortable, easy to evolve)

When to apply

Use when:

• Building or refactoring React components
• Working in Next.js (App Router) on RSC boundaries, Server Actions, data fetching
• Reviewing PRs for performance regressions
• Bundle size increases / slow HMR / cold start issues
• UI jank / unnecessary re-renders / hydration issues

Review method (prioritized)

1. Start with CRITICAL rules first (waterfalls + bundle).
2. Only then go to HIGH (server patterns + serialization).
3. Then MEDIUM (re-render + rendering).
4. Then LOW-MEDIUM micro-optimizations (JS hot paths).

Section ordering lives in: `references/rules/_sections.md`

How to use the rules efficiently

Search by keyword

rg -n "waterfall|Promise\\.all|defer await" references/rules
rg -n "barrel|optimizePackageImports|dynamic" references/rules
rg -n "cache\\(|React\\.cache|serialization|RSC" references/rules
rg -n "memo\\(|useMemo|useCallback|dependencies" references/rules

Search by tag

Each rule has tags: in YAML frontmatter.

rg -n "tags:.*bundle" references/rules
rg -n "tags:.*rerender" references/rules

Output format (recommended)

When reviewing code, output:

1. Summary (1 paragraph)
2. Critical fixes (must-fix, biggest wins)
3. High impact (should-fix)
4. Medium / Low (nice-to-have)

For each issue include:

• Rule name (and file under references/rules/)
• Location (path:line)
• Why it matters (latency / bundle / CPU / UX)
• Minimal fix direction (prefer small diffs)

If running in a Ship Faster run directory, persist the report to:

• run_dir/evidence/react-best-practices-review.md

Rule library

Rules live in:

• `references/rules/`
• Rule template: `references/rules/_template.md`