code: function(e) {
  
  		pathPrefixes = env.opts._.reduce(function(result, fileOrDir) {
  			fileOrDir = path.resolve( path.normalize(fileOrDir) );
  			if ( fs.statSync(fileOrDir).isDirectory() ) {
  				// ensure a trailing path separator
  				if ( fileOrDir.indexOf(path.sep, fileOrDir.length - path.sep.length) < 0 ) {
  					fileOrDir += path.sep;
  				}
  				result.push(fileOrDir);
  			}
  			return result;
  		}, []);
  		resourceNamePrefixes = pluginConfig.resourceNamePrefixes || [];
  		if ( !Array.isArray(resourceNamePrefixes) ) {
  			resourceNamePrefixes = [resourceNamePrefixes];
  		}
  		resourceNamePrefixes.forEach(ensureEndingSlash);
  		while ( resourceNamePrefixes.length < pathPrefixes.length ) {
  			resourceNamePrefixes.push('');
  		}
  
  		debug("path prefixes " + JSON.stringify(pathPrefixes));
  		debug("resource name prefixes " + JSON.stringify(resourceNamePrefixes));
  	}
docs: Before all files are parsed, determine the common path prefix of all filenames
  @param {object} e Event info object