It is not a bad thing. JSLint is opinionated, and Crockford thinks that when you are using a function expression inside parentheses then you should either call that method directly or assign it to a variable, because someone else looking at it might get confused between the value of the function and the function as a value itself.
For this situation Crockford recommends:
(function () { return "helloooo"; }())
^^
Notice how is the function being called
So JSLint doesn't expect anything after the closing parentheses, that's why it said it didn't expect the .
which you are using to invoke call()
.
You can look at the Code Conventions for the Javascript Programming Language (by Crockford) to learn more about this, specifically look for the section about Functions.