diff --git a/ts/smartenv.classes.ts b/ts/smartenv.classes.ts
index 666eed5..e709d0b 100644
--- a/ts/smartenv.classes.ts
+++ b/ts/smartenv.classes.ts
@@ -2,7 +2,7 @@
 class Environment {
     public runtimeEnv:string;
     public userAgent:string;
-    public nodeVersion;
+    public nodeVersion:string;
     public isBrowser:boolean;
     public isNode:boolean;
     constructor(runtimeEnvArg,userAgentArg = "undefined") {
@@ -18,4 +18,4 @@ class Environment {
             this.nodeVersion = "undefined";
         }
     };
-}
\ No newline at end of file
+}