diff --git a/src/App.tsx b/src/App.tsx
index c6c0e6c..8ba0814 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -46,7 +46,7 @@ const App: React.FC = () => {
   ) {
     return <SessionHandler />;
   } else {
-    var timeslotid = null;
+    var timeslotid: number | null = null;
     if ("timeslot_id" in q) {
       timeslotid = q.timeslot_id;
     } else if (currentTimeslot.timeslot_id != null) {
diff --git a/src/api.ts b/src/api.ts
index 56328ba..919c3f7 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -12,7 +12,7 @@ export async function apiRequest(
   params: any,
   need_auth: boolean = true
 ): Promise<Response> {
-  let req = null;
+  var req: Promise<Response>| null = null;
   if (method === "GET") {
     req = fetch(url + qs.stringify(params, { addQueryPrefix: true }), {
       credentials: need_auth ? "include" : "omit",
diff --git a/tsconfig.json b/tsconfig.json
index f2850b7..4dc65a1 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -17,7 +17,8 @@
     "resolveJsonModule": true,
     "isolatedModules": true,
     "noEmit": true,
-    "jsx": "react"
+    "jsx": "react",
+    "noImplicitAny": false
   },
   "include": [
     "src"