Add npm version check to publish workflow

The GitHub Actions workflow now checks if the package version already exists on npm before publishing, preventing duplicate version errors. The CI/CD guide was updated to emphasize the need to bump the version before release and clarify the tagging process.

Author: JorchCortez

.github/workflows/publish.yml

@@ -28,6 +28,20 @@ jobs:
       - name: Build package
         run: npm run build
 
+      - name: Check if version exists
+        id: version-check
+        run: |
+          PACKAGE_VERSION=$(node -p "require('./package.json').version")
+          echo "version=$PACKAGE_VERSION" >> $GITHUB_OUTPUT
+          if npm view use-async-view@$PACKAGE_VERSION version 2>/dev/null; then
+            echo "❌ Version $PACKAGE_VERSION already exists on npm"
+            exit 1
+          else
+            echo "✅ Version $PACKAGE_VERSION is available"
+          fi
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+      
       - name: Publish to npm
         run: npm publish --provenance --access public
         env:

CI_CD_GUIDE.md

@@ -26,6 +26,8 @@ This repository uses GitHub Actions to automatically publish to npm when you cre
 
 ### Automated Publishing (Recommended)
 
+> ⚠️ **IMPORTANT**: You must bump the version before creating a release. npm doesn't allow publishing the same version twice.
+
 1. **Update version in package.json**
    ```bash
    npm version patch  # 1.0.0 → 1.0.1 (bug fixes)
@@ -34,7 +36,7 @@ This repository uses GitHub Actions to automatically publish to npm when you cre
    # or
    npm version major  # 1.0.0 → 2.0.0 (breaking changes)
    ```
-   This creates a git tag automatically.
+   This creates a git tag automatically (e.g., `v1.0.1`).
 
 2. **Push the tag to GitHub**
    ```bash