Run the type checker

Refs #13

.github/workflows/ci.yml

@@ -71,6 +71,28 @@ jobs:
       - name: 'Run formatter'
         run: npx prettier --ignore-unknown --check '**'
 
+  typecheck:
+    name: 'Typecheck'
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+    if: github.event_name != 'schedule'
+
+    steps:
+      - name: 'Checkout code'
+        uses: actions/[email protected]
+
+      - name: 'Set up Node.js'
+        uses: actions/[email protected]
+        with:
+          node-version-file: package.json
+          cache: ${{ !env.ACT && 'npm' || '' }}
+
+      - name: 'Install dependencies'
+        run: npm ci
+
+      - name: 'Run typechecker'
+        run: npx tsc --noEmit
+
   push:
     name: 'Push image'
     runs-on: ubuntu-22.04
@@ -81,6 +103,7 @@ jobs:
     needs:
       - build-image
       - format
+      - typecheck
 
     steps:
       - name: 'Set up flyctl'

package.json

@@ -18,7 +18,8 @@
     "@types/node": "^20.14.5",
     "prettier": "^3.3.2",
     "prettier-plugin-sh": "^0.14.0",
-    "prettier-plugin-toml": "^2.0.1"
+    "prettier-plugin-toml": "^2.0.1",
+    "typescript": "^5.5.2"
   },
   "engines": {
     "node": ">=18"