code: function explode ( filepaths ) {
  		var json, res = [];
  		filepaths.filter ( existence ).forEach ( function ( filepath ) {
  			switch ( path.extname ( filepath )) {
  				case ".json" :
  					json = grunt.file.readJSON ( filepath );
  					res.push.apply ( res, json.map ( function ( localpath ) {
  						return path.dirname ( filepath ) + "/" + localpath;
  					}));
  					break;
  				case ".js" :
  					res.push ( filepath );
  					break;
  			}
  		});
  		return res;
  	}
docs: If source is a JSON file, resolve the file
  as a new source list relative to that file.
  @param {Array<String>} filepaths
  @returns {Array<String>}