Uncaught SyntaxError: BREAK statement outside of SWITCH, FOR or WHILE loop

Ok, it looks like this is an Espruino issue caused by eval messing up the parse state.

It can be caused just by:

function test(){
 switch ("a"){
  case "a":
   eval(1);
   break;
 }
}

I've filed a bug for it here

To work around this for now, add:

function eval2(x) { return eval(x); }

and then call eval2 instead of eval - hopefully that won't mess you up too much (although the new eval won't have access to the variables in the current scope).