fixed using wrong variable format

ts/error.ts

+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() {