diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3948a65..dbbb3b4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,6 +14,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
 
+      - uses: denoland/setup-deno@v1
+        with:
+          deno-version: rc
+
       - name: lint
         if: matrix.os == 'macOS-latest'
         run: |
@@ -34,3 +38,19 @@ jobs:
         if: matrix.os == 'windows-latest'
         shell: pwsh
         run: ./install_test.ps1
+
+      - name: deno lint
+        run: deno lint
+
+      - name: check fmt
+        run: deno fmt --check
+
+      - name: check bundled file up to date
+        run: |
+          cd shell-setup
+          deno task bundle
+          if ! git --no-pager diff --exit-code ./bundled.esm.js; then
+            echo 'Bundled script is out of date, update it with `cd shell-setup; deno task bundle`.
+            exit 1
+          fi
+
diff --git a/deno.json b/deno.json
new file mode 100644
index 0000000..c13fa68
--- /dev/null
+++ b/deno.json
@@ -0,0 +1,15 @@
+{
+  "workspace": [
+    "./shell-setup"
+  ],
+  "lint": {
+    "exclude": [
+      "./shell-setup/bundled.esm.js"
+    ]
+  },
+  "fmt": {
+    "exclude": [
+      "./shell-setup/bundled.esm.js"
+    ]
+  }
+}
diff --git a/shell-setup/src/main.ts b/shell-setup/src/main.ts
index 9d15235..69084a6 100644
--- a/shell-setup/src/main.ts
+++ b/shell-setup/src/main.ts
@@ -162,8 +162,8 @@ async function updateRcFile(
   command: string | UpdateRcFile,
   backups: Backups,
 ): Promise<boolean> {
-  let prepend: string = "";
-  let append: string = "";
+  let prepend = "";
+  let append = "";
   if (typeof command === "string") {
     append = command;
   } else {