diff --git a/.github/workflows/uncommited.yml b/.github/workflows/uncommited.yml
new file mode 100644
index 0000000..14d4e34
--- /dev/null
+++ b/.github/workflows/uncommited.yml
@@ -0,0 +1,27 @@
+name: uncommited
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  changes:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        # https://github.com/actions/checkout
+        name: Checkout
+        uses: actions/checkout@v1
+      -
+        name: Build
+        run: |
+          npm install
+          npm run build
+          npm run format
+          npm prune --production
+      -
+        name: Check for uncommitted changes
+        run: |
+          if [[ `git status --porcelain` ]]; then
+            echo "##[error] found changed files after build. please 'npm run build && npm run format && npm prune --production'"
+          fi