Prevents npm publish if version already exists

Adds a workflow step to check if the package version is unpublished on npm before attempting to publish.
Skips publishing and outputs a notice when the version already exists, avoiding redundant deployments and potential errors.

Author: alexcmgit

.github/workflows/publish.yml

@@ -11,30 +11,38 @@ permissions:
   contents: read
 
 jobs:
-  publish:
+  check-version:
     runs-on: ubuntu-latest
+    outputs:
+      should_publish: ${{ steps.check.outputs.should_publish }}
+      version: ${{ steps.read_version.outputs.version }}
     steps:
-      - name: Checkout
-        uses: actions/checkout@v4
+      - uses: actions/checkout@v4
+
+      - name: Read version from package.json
+        id: read_version
+        run: echo "version=$(jq -r '.version' package.json)" >> $GITHUB_OUTPUT
 
-      - name: Check if package version is unpublished on npm
-        id: version-check
+      - name: Check if version exists on npm
+        id: check
         run: |
-          VERSION=$(jq -r '.version' package.json)
-          NAME=$(jq -r '.name' package.json)
+          echo "Checking npm for version ${{ steps.read_version.outputs.version }}"
 
-          echo "Package: $NAME"
-          echo "Version: $VERSION"
+          EXISTS=$(npm view $(jq -r '.name' package.json) versions --json | jq -e '.[] | select(.=="'${{ steps.read_version.outputs.version }}'")' || echo "no")
 
-          if npm view "$NAME@$VERSION" version > /dev/null 2>&1; then
-            echo "### 🛑 Deployment aborted" >> $GITHUB_STEP_SUMMARY
-            echo "Version $VERSION of $NAME is already published on npm." >> $GITHUB_STEP_SUMMARY
-            echo "Skipping remaining steps." >> $GITHUB_STEP_SUMMARY
-            exit 0
+          if [ "$EXISTS" = "no" ]; then
+            echo "should_publish=true" >> $GITHUB_OUTPUT
           else
-            echo "Version $VERSION of $NAME is NOT published. Continuing workflow."
+            echo "should_publish=false" >> $GITHUB_OUTPUT
           fi
 
+  publish:
+    needs: check-version
+    if: needs.check-version.outputs.should_publish == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
       - uses: actions/setup-node@v4
         with:
           node-version: '25'
@@ -43,6 +51,17 @@ jobs:
 
       - name: Update npm
         run: npm install -g npm@latest
+
       - run: npm ci
       - run: npm run build
-      - run: npm publish --access public
+
+      - name: Publish package
+        run: npm publish --access public
+
+  skip-notice:
+    needs: check-version
+    if: needs.check-version.outputs.should_publish == 'false'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Version already published
+        run: echo "Version ${{ needs.check-version.outputs.version }} already exists on npm. Skipping publish."