How to force google closure compiler to keep "use strict"; in the compiled js code?

Question

If you're using the module pattern and have something like this:

(function () {
   "use strict";
   // this function is strict...
}());

and compile the code using the Google Closure Compiler, the "use strict"; directive will not make it into the compiled file.

So how do you prevent the Closure Compiler from removing the ES5/strict directive?

(Note that I don't want to use the other mode of enforcing ES5/strict mode, which is to simply add the "use strict"; to the first line of the compiled file. I want to use the module pattern as described here.)

Answer 1

Update: strict mode is now supported in the compiler.

Just use --language_in=ECMASCRIPT5_STRICT.

References:

http://code.google.com/p/closure-compiler/issues/detail?id=69

http://code.google.com/p/closure-compiler/source/detail?r=873

http://code.google.com/p/closure-compiler/source/detail?r=1114