In the code-fragment above the closing bracket of the constructor is missing. I can’t tell if this is the problem though, because the source code is not complete and you might removed it by mistake when pasting. I would recommend you to use an editor with syntax checking and Intellisense support such as VS Code.
Without seeing the complete code of the doRadio() method (because it’s also only partial code sample) I can only guess why it’s not working. But most probably there’s an error in your code/implementation or you’re missing an import. The reason for the blank screen is something related to the following issue, I guess:
So the problem is that when doRadio runs, i do in fact get the alert. user can then change to one of the 4 options and the data is set in localstorage. The alert closes and the app is no longer usable. Its as if everything is frozen. Like the alert modal has still taken control even though its no loner visible