refactor: migrate to TypeScript with Vitest and modern tooling

BREAKING CHANGE: @actions/github upgraded from v2 to v6

## Changes

### TypeScript Migration
- Convert index.js to src/index.ts with strict TypeScript mode
- Extract pure utility functions to src/utils.ts for testability
- Add tsconfig.json with strict compiler options

### Testing Framework
- Replace Jest with Vitest for faster, ESM-native testing
- Add comprehensive unit tests for utility functions (43 tests)
- Add integration tests for GitHub Action structure (12 tests)
- Target: 80%+ code coverage

### @actions/github v6 Upgrade
- Migrate from deprecated `new github.GitHub(token)` to `github.getOctokit(token)`
- Update all API calls from `octokit.repos.*` to `octokit.rest.repos.*`
- Update all API calls from `octokit.issues.*` to `octokit.rest.issues.*`
- Update all API calls from `octokit.git.*` to `octokit.rest.git.*`

### ESLint Configuration
- Enable TypeScript support in @antfu/eslint-config
- Replace Jest globals with Vitest globals (vi instead of jest)
- Add lib/ to ignore patterns

### Build System
- Update ncc build to compile TypeScript directly
- Add source maps and licenses to dist output
- Add typecheck script for standalone type checking
- Update all npm scripts for TypeScript workflow

### Files Deleted
- index.js (migrated to src/index.ts)
- index.test.js (migrated to src/__tests__/*.test.ts)
- jest.config.js (replaced by vitest.config.ts)
- now.js (unused legacy file)

Closes #291

Author: amondnet

.github/workflows/claude-code-review.yml

@@ -3,40 +3,40 @@ name: Basic PR Review with Claude
 on:
   pull_request:
     types: [opened, synchronize, reopened, ready_for_review]
-  
+
   # Manual trigger for testing
   workflow_dispatch:
 
 jobs:
   claude-review:
     name: Claude Code Review
     runs-on: ubuntu-latest
-    
+
     # Skip draft PRs unless manually triggered
     if: github.event.pull_request.draft == false || github.event_name == 'workflow_dispatch'
-    
+
     permissions:
       contents: read
       pull-requests: write
       id-token: write
-    
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      
+
       - name: Run Claude Code Review
         uses: amondnet/claude-code-review@main
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
-          review_type: 'comprehensive'
+          review_type: comprehensive
           progress_tracking: true
           severity_labels: true
           max_review_comments: 30
           exclude_paths: 'node_modules,dist,build,.git,*.lock'
           github_token: ${{ secrets.GITHUB_TOKEN }}
-      
+
       - name: Review Complete Notification
         if: always()
         run: |

.please/memory/session-summary.md

@@ -0,0 +1,39 @@
+# Session Summary: TypeScript and Vitest Migration
+
+## Feature Description
+Migrate vercel-action from JavaScript to TypeScript with modern tooling:
+1. Convert index.js to TypeScript (src/index.ts)
+2. Replace Jest with Vitest for testing
+3. Update @antfu/eslint-config for TypeScript support
+
+## Requirements Summary
+- TypeScript source files in `src/` directory
+- Strict TypeScript mode enabled
+- Delete deprecated `now.js` file
+- Maintain backward compatibility with action inputs/outputs
+- Keep dist/index.js as bundled output
+
+## Constraints
+- GitHub Action must remain functional
+- Node 20 runtime requirement
+- ncc bundling for dist/
+
+## Current Phase: Codebase Exploration
+
+## Key Decisions
+- [x] Source directory: `src/`
+- [x] TypeScript strict mode: enabled
+- [x] Delete now.js: yes
+
+## Files to Modify
+- index.js → src/index.ts
+- index.test.js → src/index.test.ts
+- package.json (scripts, dependencies)
+- eslint.config.mjs (TypeScript support)
+- jest.config.js → vitest.config.ts
+- action.yml (verify dist path)
+- tsconfig.json (new)
+
+## Progress
+- [x] Phase 1: Discovery - Complete
+- [ ] Phase 2: Codebase Exploration - In Progress

.please/memory/tasklist.json

@@ -0,0 +1,43 @@
+{
+  "session_id": "20251212-typescript-vitest-migration",
+  "feature_name": "TypeScript and Vitest Migration",
+  "created_at": "2025-12-12T00:00:00Z",
+  "updated_at": "2025-12-12T00:00:00Z",
+  "status": "in_progress",
+  "current_phase": 6,
+  "issue_number": 291,
+  "branch": "291-refactor-migrate-to-typescript-with-vitest-and-modern-tooling",
+  "phases": [
+    { "number": 1, "name": "Discovery", "status": "completed", "started_at": "2025-12-12T00:00:00Z", "completed_at": "2025-12-12T00:01:00Z" },
+    { "number": 2, "name": "Codebase Exploration", "status": "completed", "started_at": "2025-12-12T00:01:00Z", "completed_at": "2025-12-12T00:02:00Z" },
+    { "number": 3, "name": "Clarifying Questions", "status": "completed", "completed_at": "2025-12-12T00:03:00Z" },
+    { "number": 4, "name": "Architecture Design", "status": "completed", "completed_at": "2025-12-12T00:04:00Z" },
+    { "number": 5, "name": "GitHub Issue & PR", "status": "completed", "completed_at": "2025-12-12T00:05:00Z" },
+    { "number": 6, "name": "Implementation", "status": "completed", "completed_at": "2025-12-12T00:22:00Z" },
+    { "number": 7, "name": "Quality Review", "status": "in_progress", "started_at": "2025-12-12T00:22:00Z" },
+    { "number": 8, "name": "PR Finalization", "status": "pending" }
+  ],
+  "tasks": [
+    { "id": "T001", "title": "Create tsconfig.json with strict settings", "phase": 6, "status": "pending", "parallel": true, "dependencies": [] },
+    { "id": "T002", "title": "Update package.json (add TypeScript, Vitest; remove Jest)", "phase": 6, "status": "pending", "parallel": true, "dependencies": [] },
+    { "id": "T003", "title": "Update eslint.config.mjs for TypeScript + Vitest globals", "phase": 6, "status": "pending", "parallel": true, "dependencies": [] },
+    { "id": "T004", "title": "Create vitest.config.ts", "phase": 6, "status": "pending", "parallel": true, "dependencies": [] },
+    { "id": "T005", "title": "Create src/utils.ts with pure utility functions", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T001", "T002", "T003", "T004"] },
+    { "id": "T006", "title": "Create src/__tests__/utils.test.ts with unit tests", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T005"] },
+    { "id": "T007", "title": "Create src/index.ts with main action logic", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T005"] },
+    { "id": "T008", "title": "Upgrade @actions/github to v6 and update API calls", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T007"] },
+    { "id": "T009", "title": "Create src/__tests__/index.test.ts", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T007", "T008"] },
+    { "id": "T010", "title": "Delete old files (index.js, index.test.js, jest.config.js, now.js)", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T007", "T009"] },
+    { "id": "T011", "title": "Build and verify dist/index.js", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T010"] },
+    { "id": "T012", "title": "Run all quality checks (lint, typecheck, test)", "phase": 6, "status": "pending", "parallel": false, "dependencies": ["T011"] }
+  ],
+  "decisions": {
+    "source_directory": "src/",
+    "keep_now_js": false,
+    "typescript_strict": true,
+    "modularize": false,
+    "add_comprehensive_tests": true,
+    "upgrade_github_api": true,
+    "split_utils": true
+  }
+}

dist/index.d.ts

@@ -0,0 +1 @@
+export {};