Uglify mangle

Hi there, I modified the jsTask like this:

var jsTasks = function(filename) {
  return lazypipe()
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.init());
    })
    .pipe(concat, filename)
    .pipe(function() {
      return gulpif(argv.production, uglify({
        mangle: true
      }));
    })
    .pipe(function() {
      return gulpif(enabled.rev, rev());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.write('.'));
    })();
};

The uglifying works, but it doesn’t mangle the variables. Any ideas?

Sorry, just noticed that mangle actually does work, just the top-level variables won’t be mangled, which is a (very sane) default if uglifyjs.