diff --git a/ts/error.ts b/ts/error.ts
index e7dbccf9884382950f902d276709a76f92dd9ae3..da31c3c4bb5522c89019041722abc4f540efe7f0 100644
--- a/ts/error.ts
+++ b/ts/error.ts
@@ -1,3 +1,5 @@
+import Timeout = NodeJS.Timeout;
+
 let intervalTime = 150;
 
 let terminal:HTMLElement = <HTMLElement> document.getElementsByClassName("terminal")[0];
@@ -6,7 +8,7 @@ let promptContainer:HTMLElement = <HTMLElement> terminal.getElementsByClassName(
 
 let dataIndex = 0;
 let stringPosition = 0;
-let printTask: number;
+let printTask: Timeout;
 
 function writeOut() {