TypeScript Project Review

Overview

This skill provides specialized review guidance for TypeScript projects, focusing on type safety, best practices, and effective use of TypeScript's type system. It orchestrates Context7 MCP for generic TypeScript documentation while enforcing project-specific type safety policies.

Context7 Integration

Generic TypeScript Documentation

Delegate generic TypeScript questions to Context7 MCP with library ID /websites/typescriptlang or /microsoft/typescript:

Type Guards and Unknown:

Query: "TypeScript type guards unknown types implementation"
Result: typeof, instanceof, user-defined type predicates

Generics and Constraints:

Query: "TypeScript generics type constraints examples"
Result: Generic type parameters, extends keyword, default types

Union and Intersection Types:

Query: "TypeScript discriminated unions intersection types"
Result: Union type narrowing, tagged unions, type composition

Utility Types:

Query: "TypeScript utility types Partial Pick Omit Record"
Result: Built-in utility types for type transformations

tsconfig.json Options:

Query: "TypeScript strict mode compiler options configuration"
Result: strict, noImplicitAny, strictNullChecks, etc.

Performance Optimization:

Query: "TypeScript compilation performance bundle size optimization"
Result: type-only imports, tree shaking, build performance

When to Use Context7

• •✅ Generic TypeScript syntax and features
• •✅ Compiler options explanations
• •✅ Built-in utility types
• •✅ Standard type patterns
• •❌ Project-specific type safety policies (see below)
• •❌ Code review criteria (see below)

Project-Specific Type Safety Policy

Zero-Any Policy

Goal: Eliminate all any types from codebase

Strategies: Replace any with unknown + type guards, use type inference, define explicit interfaces, implement user-defined type guards

Justification Required: If any is truly necessary, document why

Result Type Pattern (Recommended)

Pattern: type Result<T, E> = { success: true; data: T } | { success: false; error: E };

Benefits: Type-safe error handling, explicit success/failure states, no exception throwing, composable discriminated unions

Type Assertion Guidelines

Minimize: Avoid as type assertions whenever possible

Prefer: Type guards and type narrowing (data is Type predicates)

Strict Mode Compliance

Required: strict: true, noImplicitAny: true, strictNullChecks: true in tsconfig.json

Verification: Check tsconfig.json compilerOptions, scan codebase for any types

⭐️ 5-Star Evaluation Criteria

Type Safety Assessment

⭐⭐⭐⭐⭐ (5/5) Excellent: Zero any, minimal type assertions, active type guards, full strict mode, Result<T,E> pattern

⭐⭐⭐⭐☆ (4/5) Good: Rare justified any, controlled assertions, good type guard coverage, most strict flags enabled

⭐⭐⭐☆☆ (3/5) Standard: Some any usage, moderate assertions, basic type guards, partial strict mode

⭐⭐☆☆☆ (2/5) Needs Improvement: Frequent any, heavy assertion reliance, missing type guards, strict mode not enabled

⭐☆☆☆☆ (1/5) Requires Overhaul: Pervasive any, type system circumvented, no type guards, minimal TypeScript benefit

Type Definition Quality

Interface design clarity, generic usage appropriateness, type reusability, documentation completeness, discriminated union patterns

Compiler Utilization

Strict mode configuration, compiler options, build configuration, ESLint + TypeScript integration

Review Workflow

When reviewing TypeScript code:

1. •Check tsconfig.json: Verify strict mode and compiler options
2. •Scan for any: Identify and eliminate any type usage
3. •Review type assertions: Minimize and justify all assertions
4. •Evaluate type definitions: Assess interfaces, types, and generics
5. •Check error handling: Verify Result<T,E> pattern or type-safe alternatives
6. •Test type narrowing: Ensure proper type guards
7. •Verify tool integration: Check ESLint and TypeScript alignment
8. •Assess performance: Consider compilation and bundle impact

🤖 Agent Integration

このスキルはTypeScriptプロジェクトを扱うエージェントに専門知識を提供します:

Error-Fixer Agent

• •提供内容: TypeScript型エラー修正、any型排除戦略、strictモード対応
• •タイミング: TypeScriptエラー修正・型安全性向上時
• •コンテキスト: 型エラー自動修正、any→unknown変換、型ガード実装、tsconfig.json最適化

Code-Reviewer Agent

• •提供内容: TypeScript型安全性評価基準、ベストプラクティス
• •タイミング: TypeScriptコードレビュー時
• •コンテキスト: ⭐️5段階評価、型アサーション評価、Result<T,E>パターン、パフォーマンス影響

Orchestrator Agent

• •提供内容: TypeScriptプロジェクト構成、アーキテクチャパターン
• •タイミング: TypeScript機能実装・リファクタリング時
• •コンテキスト: モジュール構成、型定義ファイル管理、コンパイラオプション設定

自動ロード条件

• •"TypeScript"、"TS"、"型エラー"、"型安全性"に言及
• •.ts、.tsx、tsconfig.jsonファイル操作時
• •TypeScriptコンパイルエラー対応時
• •プロジェクト検出: TypeScriptプロジェクト

統合例:

ユーザー: "TypeScriptの型エラーを修正してany型を排除"
    ↓
TaskContext作成
    ↓
プロジェクト検出: TypeScript + React
    ↓
スキル自動ロード: typescript, react
    ↓
Context7クエリ: 型ガード実装パターン
    ↓
エージェント選択: error-fixer
    ↓ (スキルコンテキスト提供)
TypeScript型エラー修正パターン + any型排除戦略
    ↓
実行完了（型安全性向上、strictモード準拠）

Integration with Related Skills

• •react skill: For React + TypeScript projects
• •clean-architecture skill: For TypeScript architecture patterns
• •security skill: For type-safe security implementations