gruntjs/grunt-contrib-concat — pull request #100 by mbaaz (2014-09-10 11:12:39+00:00)
Title: added new option: skipWhenSourceEmpty

With this boolean flag you can opt out of writing files that contain no source files.

Sometimes a pattern do not match any files, and in those cases, you can opt out of having an empty file written to destination. This will also work when no source file/pattern is specified at all.