You can use
{{Layer["InSideLayer"+ index]}}
your code {{Layer.InSideLayer +''+ index}}
won't work as you are actually concatenating it on runtime so it will return it as undefined.
You can use
{{Layer["InSideLayer"+ index]}}
your code {{Layer.InSideLayer +''+ index}}
won't work as you are actually concatenating it on runtime so it will return it as undefined.