Following docs - sendTokenToServer() is not defined & showToken() is not defined

I've looked through issues and don't see this present. I have a code pen that shows code exactly. Everything seems to be working up to line 38 where. Before that I'll log the token out with `messaging.getToken();` but on line 38 when `sendTokenToServer(currentToken)` is used is when I'm told that `sendTokenToServer` is not defined. Further below within the catch on line 288 I'm told that `showToken()` is also not defined.

This seems very easy but for some reason I can't get past why these certain methods are undefined and others before them aren't. Any help would be much appreciated. I'm following docs exactly but I'm only on the first page.

[Code Pen - Firebase Implementation](https://codepen.io/danj210/pen/ZmZQNE?editors=0010)