Merge pull request #81 from karma-runner/fix-omitted-option-error

fix: optional option no longer trigger an error when omitted

lib/preprocessor.js

@@ -4,7 +4,7 @@ var istanbul  = require('istanbul'),
 
 var createCoveragePreprocessor = function(logger, basePath, reporters, coverageReporter) {
   var log = logger.create('preprocessor.coverage');
-  var instrumenterOverrides = coverageReporter.instrumenter || {};
+  var instrumenterOverrides = (coverageReporter && coverageReporter.instrumenter) || {};
   var instrumenters = {istanbul: istanbul, ibrik: ibrik};
 
   // if coverage reporter is not used, do not preprocess the files