diff --git a/test/unit/socket-close-test.ts b/test/unit/socket-close-test.ts
index 94443693..a12bf031 100644
--- a/test/unit/socket-close-test.ts
+++ b/test/unit/socket-close-test.ts
@@ -113,7 +113,7 @@ for (const proto of testProtos("tcp", "ipc", "inproc")) {
         let weakRef: undefined | WeakRef<any>
 
         const task = async () => {
-          let context: zmq.Context | undefined = new zmq.Context()
+          const context: zmq.Context | undefined = new zmq.Context()
           const socket = new zmq.Dealer({context, linger: 0})
           weakRef = new WeakRef(context)
 
diff --git a/tsconfig.json b/tsconfig.json
index 8a0b6b27..e3ebf8a2 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,7 +5,7 @@
     "declaration": true,
     "module": "commonjs",
     "types": [
-      "node",
+      "node"
     ],
     "strictPropertyInitialization": false, // TODO
     "strict": true,