Implement ESM + Wrangler approach for Cloudflare Workers testing

- Replace complex test approaches with simple ESM + Wrangler solution
- Create test worker that runs Jest-style tests in Cloudflare Workers environment
- Use ESM (native Cloudflare Workers module system) instead of CommonJS
- Run tests in actual Cloudflare Workers runtime using wrangler dev
- Avoid mime-db CommonJS compatibility issues by using ESM
- Test optional types work correctly in Cloudflare Workers context
- Add comprehensive GitHub Actions workflows for automated testing
- Update documentation to reflect new ESM approach

This approach is much cleaner and more accurate than previous methods, testing our SDK in the exact environment where users will run it.

Author: cursoragent

.github/workflows/README.md

@@ -4,50 +4,39 @@ This directory contains GitHub Actions workflows for testing the Nylas Node.js S
 
 ## Workflows
 
-### `cloudflare-simple-test.yml`
-**Recommended approach** - Simple and effective Cloudflare Workers testing:
-- Uses Cloudflare's `nodejs_compat` environment to test our existing SDK
-- Runs compatibility tests locally without requiring Cloudflare deployment
-- Tests both CommonJS and ESM builds
+### `cloudflare-simple-test.yml` & `cloudflare-esm-test.yml`
+**Recommended approach** - ESM + Wrangler testing:
+- Uses ESM (ECMAScript Modules) for better Cloudflare Workers compatibility
+- Runs our normal test suites in actual Cloudflare Workers environment using Wrangler
+- Tests locally using `wrangler dev` to simulate production environment
 - Validates optional types work correctly in Cloudflare Workers context
 - Optional deployment testing (requires secrets)
 
-### `cloudflare-nodejs-compat-test.yml`
-More comprehensive testing using Cloudflare Workers:
-- Creates a test worker that runs SDK tests in `nodejs_compat` environment
-- Tests locally using `wrangler dev`
-- Validates SDK functionality in actual Cloudflare Workers runtime
-
-### `cloudflare-vitest-test.yml`
-Advanced testing using Cloudflare's Vitest integration:
-- Uses `@cloudflare/vitest-pool-workers` for integration testing
-- Runs tests directly in Cloudflare Workers context
-- More sophisticated testing setup
-
 ## Why This Approach Works
 
-### **Cloudflare `nodejs_compat` Environment**
-- Cloudflare Workers supports Node.js compatibility through the `nodejs_compat` flag
-- This allows us to run our existing Node.js code (including the Nylas SDK) in Cloudflare Workers
-- We can test the exact same code that users will run in production
+### **ESM + Wrangler Environment**
+- Uses ESM which is the native module system for Cloudflare Workers
+- Runs tests in actual Cloudflare Workers runtime using Wrangler
+- Tests the exact same code that users will run in production
+- Avoids CommonJS compatibility issues (like mime-db problems)
 
 ### **Testing Optional Types**
 The main issue we're addressing is ensuring optional types work correctly in Cloudflare Workers. Our tests verify:
-- SDK can be imported in Cloudflare Workers context
+- SDK can be imported in Cloudflare Workers context using ESM
 - Client can be created with minimal configuration (tests optional types)
 - All optional properties work without TypeScript errors
-- Both CommonJS and ESM builds are compatible
+- ESM builds are fully compatible with Cloudflare Workers
 
 ## Local Testing
 
 You can test Cloudflare Workers compatibility locally:
 
 ```bash
-# Run the compatibility test
+# Run the ESM + Wrangler test
 npm run test:cloudflare
 
 # Or run the test script directly
-node test-cloudflare-compat.js
+node run-tests-cloudflare.mjs
 ```
 
 ## GitHub Actions Setup

.github/workflows/cloudflare-esm-test.yml

@@ -0,0 +1,88 @@
+name: Cloudflare Workers ESM Test
+
+on:
+  push:
+    branches:
+      - cursor/add-cloudflare-worker-to-test-matrix-3aca
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  test-in-cloudflare-workers:
+    name: Test in Cloudflare Workers with ESM
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Wrangler CLI
+        run: npm install -g wrangler@latest
+
+      - name: Build the SDK
+        run: npm run build
+
+      - name: Run tests in Cloudflare Workers environment
+        run: |
+          echo "🧪 Running Nylas SDK tests in Cloudflare Workers environment..."
+          node run-tests-cloudflare.mjs
+
+      - name: Test with wrangler deploy --dry-run
+        run: |
+          cd cloudflare-test-worker
+          echo "🔍 Testing worker build and deployment readiness..."
+          wrangler deploy --dry-run
+          echo "✅ Worker is ready for deployment"
+
+  # Optional: Deploy and test in actual Cloudflare environment
+  deploy-and-test:
+    name: Deploy and Test in Cloudflare
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main' && github.event_name == 'push' && secrets.CLOUDFLARE_API_TOKEN != ''
+    needs: test-in-cloudflare-workers
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build the SDK
+        run: npm run build
+
+      - name: Deploy test worker to Cloudflare
+        uses: cloudflare/wrangler-action@v3
+        with:
+          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+          command: deploy
+          workingDirectory: cloudflare-test-worker
+
+      - name: Test deployed worker
+        run: |
+          # Wait for deployment
+          sleep 30
+          
+          # Get worker URL
+          WORKER_URL=$(cd cloudflare-test-worker && npx wrangler whoami --format json | jq -r '.subdomain')
+          echo "Testing worker at: https://${WORKER_URL}.workers.dev"
+          
+          # Run tests against deployed worker
+          curl -f "https://${WORKER_URL}.workers.dev/test" | jq .