lint-test-typecheck-policy

Lint, Test, Typecheck Policy

Overview

Policy สำหรับ enforce code quality standards ผ่าน automated checks: linting, testing, type checking - ต้องผ่านทุกอย่างก่อน merge

Why This Matters

• Quality: จับ bugs ก่อนถึง production
• Consistency: Code style เหมือนกันทั้ง team
• Safety: Type errors จับได้ตั้งแต่ compile time
• Automated: ไม่ต้องพึ่ง manual review

Three Pillars

1. Lint (Code Style)

# Must pass
npm run lint

# Zero errors, zero warnings
✓ 0 errors
✓ 0 warnings

2. Test (Correctness)

# Must pass
npm test

# All tests pass, coverage ≥80%
✓ 150 tests passing
✓ Coverage: 85%

3. Typecheck (Type Safety)

# Must pass
npm run typecheck

# Zero type errors
✓ 0 errors

CI Pipeline

# .github/workflows/quality-gates.yml
name: Quality Gates
on: [pull_request]

jobs:
  quality:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
      
      - name: Install
        run: npm ci
      
      - name: Lint
        run: npm run lint
        # Fails on any error/warning
      
      - name: Type Check
        run: npm run typecheck
        # Fails on any type error
      
      - name: Test
        run: npm test -- --coverage
        # Fails if coverage < 80%
      
      - name: Upload Coverage
        uses: codecov/codecov-action@v3

Lint Configuration

ESLint

// .eslintrc.js
module.exports = {
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
  ],
  rules: {
    // Errors (must fix)
    'no-console': 'error',
    'no-debugger': 'error',
    '@typescript-eslint/no-explicit-any': 'error',
    '@typescript-eslint/no-unused-vars': 'error',
    
    // Warnings (should fix)
    'complexity': ['warn', 10],
    'max-lines': ['warn', 300],
  }
};

Prettier

{
  "semi": true,
  "singleQuote": true,
  "tabWidth": 2,
  "trailingComma": "es5"
}

Test Policy

Coverage Requirements

{
  "jest": {
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": 80
      }
    }
  }
}

Test Types Required

✓ Unit tests (all functions)
✓ Integration tests (critical paths)
✓ E2E tests (user flows)

TypeScript Configuration

{
  "compilerOptions": {
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true
  }
}

Pre-commit Hooks

{
  "husky": {
    "hooks": {
      "pre-commit": "lint-staged"
    }
  },
  "lint-staged": {
    "*.ts": [
      "eslint --fix",
      "prettier --write",
      "npm run typecheck"
    ],
    "*.test.ts": [
      "npm test -- --findRelatedTests"
    ]
  }
}

Summary

Quality Gates: Lint + Test + Typecheck ต้องผ่านทั้งหมด

Requirements:

• Lint: 0 errors, 0 warnings
• Test: All pass, ≥80% coverage
• Typecheck: 0 type errors

Enforcement:

• CI pipeline (blocks merge)
• Pre-commit hooks (local)
• Code review (manual check)

No exceptions: ต้องผ่านทุกอย่าง