diff --git a/src/App.tsx b/src/App.tsx
index 637a0ac..baee6d1 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -82,7 +82,7 @@ function App(): React.JSX.Element {
         />
       </section>
 
-      {state.loading === true ? (
+      {state.loading ? (
         <LoadingSpinner />
       ) : state.error !== null ? (
         <ErrorMessage
diff --git a/src/components/ActivityChart.tsx b/src/components/ActivityChart.tsx
index 578e7a1..e2793a8 100644
--- a/src/components/ActivityChart.tsx
+++ b/src/components/ActivityChart.tsx
@@ -9,7 +9,7 @@ interface ActivityChartProps {
 }
 
 export function ActivityChart({ activities, type }: ActivityChartProps): React.JSX.Element {
-  const spec: VisualizationSpec = useMemo(() => ({
+  const spec = useMemo((): VisualizationSpec => ({
     $schema: 'https://vega.github.io/schema/vega-lite/v5.json',
     data: {
       values: activities
diff --git a/tsconfig.app.json b/tsconfig.app.json
index c1a90cc..b0da93d 100644
--- a/tsconfig.app.json
+++ b/tsconfig.app.json
@@ -42,6 +42,6 @@
     "allowJs": false,
     "checkJs": false
   },
-  "include": ["src"],
+  "include": ["src", "*.ts"],
   "exclude": ["node_modules"]
 }