Javascript / Expected ')' and instead saw '; [on hold]

dbRefObject.on("value", snap => {
 output="preObject".stringify;
  getElementById("Punkte1").innerHTML = "Punkte =" + output;
};

Hello, i cant figure out what's the problem

This is a snipset of "Firebase"'s Api and me trying to use what the database sent me in my app.

The exact error is : JSHint Warning W116 - Expected ')' and instead saw ';'.at line 25 col 6 in HTML\Firebase.js

From Jshint but im also getting the same error in the Dev console in Chrome.