code-reviewer-nodejs

Positioning

Focused on Node.js runtime and backend development patterns review. Checks async correctness, resource management, and middleware design.

Difference from code-reviewer-typescript: TS skill focuses on compile-time type system; this skill focuses on runtime behavior. Difference from code-reviewer-react: React skill focuses on frontend components; this skill focuses on backend services.

Execution timing: When reviewing Node.js backend code (routes, middleware, service layer, CLI tools, etc.) Scan scope: Specified files, or file list obtained via git diff

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Review Process

Step 1: Determine Review Scope

1. Files or directories explicitly specified by user
2. User mentions PR or branch → run git diff --name-only <base>..HEAD
3. None of the above → ask user which files to review

Only review backend-related .ts / .js / .mjs / .cjs files. Skip test files, type declarations, config files, and frontend component files.

Step 2: Per-file Review

Read the complete file content first, understand context, then check each item.

Step 3: Summary Report

Generate a structured report using the output template at the bottom.

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Review Checklist

1. Async Patterns

Node.js's async model is its core characteristic — incorrect async handling is the primary source of backend bugs.

Check items:

• Whether async/await has complete try-catch error handling
• Whether unawaited Promises exist (fire-and-forget must explicitly state intent)
• Whether Promise concurrency is appropriate — Promise.all vs Promise.allSettled choice
• Whether callback hell exists (callbacks nested more than 3 levels deep) → refactor to async/await
• Whether errors in Promise.all would cause other task results to be lost → consider allSettled
• Concurrency control — whether concurrency limits are needed (e.g., batch API calls)

2. Event Loop

Blocking the event loop is a fatal issue for Node.js services.

Check items:

• Whether synchronous blocking operations (fs.readFileSync, crypto.pbkdf2Sync, etc.) exist in request handling paths
• Whether CPU-intensive tasks consider Worker Threads or process pools
• Whether process.nextTick vs setImmediate usage is correct
• Whether large loops or recursion could block the event loop
• Whether timers (setInterval/setTimeout) have cleanup mechanisms
• Whether event listener leaks exist (EventEmitter maxListeners warning)