Update publish.yml

Author: vanderbr

.github/workflows/publish.yml

@@ -39,7 +39,35 @@ jobs:
       - name: Build
         run: pnpm build
 
+      - name: Preflight publish checks
+        id: preflight
+        shell: bash
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+        run: |
+          set -euo pipefail
+          if [ -z "${NODE_AUTH_TOKEN:-}" ]; then
+            echo "NPM_TOKEN is not configured."
+            exit 1
+          fi
+          npm whoami >/dev/null
+
+          PKG_NAME="$(node -p "require('./package.json').name")"
+          PKG_VERSION="$(node -p "require('./package.json').version")"
+          echo "package_name=${PKG_NAME}" >> "$GITHUB_OUTPUT"
+          echo "package_version=${PKG_VERSION}" >> "$GITHUB_OUTPUT"
+
+          if npm view "${PKG_NAME}@${PKG_VERSION}" version >/dev/null 2>&1; then
+            echo "Version ${PKG_NAME}@${PKG_VERSION} already exists on npm. Skipping publish."
+            echo "should_publish=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          echo "Version ${PKG_NAME}@${PKG_VERSION} is not published yet."
+          echo "should_publish=true" >> "$GITHUB_OUTPUT"
+
       - name: Publish
+        if: steps.preflight.outputs.should_publish == 'true'
         run: npm publish --provenance --access public
         env:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}