Add the check-dist workflow

.github/workflows/check-dist.yml

@@ -0,0 +1,63 @@
+# In JavaScript actions, `dist/` is a special directory. When you reference
+# an action with the `uses:` property, `dist/index.js` is the code that will be
+# run. For this project, the `dist/index.js` file is transpiled from other
+# source files. This workflow ensures the `dist/` directory contains the
+# expected transpiled code.
+#
+# If this workflow is run from a feature branch, it will act as an additional CI
+# check and fail if the checked-in `dist/` directory does not match what is
+# expected from the build.
+name: Check Transpiled JavaScript
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  check-dist:
+    name: Check dist/
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+          cache: npm
+      - name: Install Dependencies
+        run: npm ci
+      - name: Build dist/ Directory
+        run: npm run bundle
+
+      # This will fail the workflow if the `dist/` directory is different than
+      # expected.
+      - name: Compare Directories
+        id: diff
+        run: |
+          if [ ! -d dist/ ]; then
+            echo "Expected dist/ directory does not exist.  See status below:"
+            ls -la ./
+            exit 1
+          fi
+          if [ "$(git diff --ignore-space-at-eol --text dist/ | wc -l)" -gt "0" ]; then
+            echo "Detected uncommitted changes after build. See status below:"
+            git diff --ignore-space-at-eol --text dist/
+            exit 1
+          fi
+
+      # If `dist/` was different than expected, upload the expected version as a
+      # workflow artifact.
+      - if: ${{ failure() && steps.diff.outcome == 'failure' }}
+        name: Upload Artifact
+        id: upload
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/