Compression option

[optimalisatie]

First of all thanks for the great Grunt plugin! We have been using it in many projects.

We currently require to modify the output manually to achieve better compression. For example, it is possible to create a IIFE using !function(){}() which would save some extra bytes.

If you would ever want to improve the plugin, I hereby want to suggest to add a compression option including unary_operator option.

!function(){ /* code */ }();   // returns true by default
~function(){ /* code */ }();   // returns -1 by default
-function(){ /* code */ }();   // returns NaN by default
+function(){ /* code */ }();   // returns NaN by default

More IIFE techniques are available on https://digitalfortress.tech/js/exclamation-mark-function-iife/