Only add frontend code coverage instrumentation when generating coverage report

1 files changed, 14 insertions, 18 deletions

diff --git a/config/karma.config.js b/config/karma.config.js
index c1d3751d88f..eb082dd28bf 100644
--- a/config/karma.config.js
+++ b/config/karma.config.js
@@ -3,17 +3,6 @@ var webpack = require('webpack');
 var webpackConfig = require('./webpack.config.js');
 var ROOT_PATH = path.resolve(__dirname, '..');
 
-// add coverage instrumentation to babel config
-if (webpackConfig.module && webpackConfig.module.rules) {
-  var babelConfig = webpackConfig.module.rules.find(function (rule) {
-    return rule.loader === 'babel-loader';
-  });
-
-  babelConfig.options = babelConfig.options || {};
-  babelConfig.options.plugins = babelConfig.options.plugins || [];
-  babelConfig.options.plugins.push('istanbul');
-}
-
 // remove problematic plugins
 if (webpackConfig.plugins) {
   webpackConfig.plugins = webpackConfig.plugins.filter(function (plugin) {
@@ -27,7 +16,8 @@ if (webpackConfig.plugins) {
 // Karma configuration
 module.exports = function(config) {
   var progressReporter = process.env.CI ? 'mocha' : 'progress';
-  config.set({
+
+  var karmaConfig = {
     basePath: ROOT_PATH,
     browsers: ['PhantomJS'],
     frameworks: ['jasmine'],
@@ -38,14 +28,20 @@ module.exports = function(config) {
     preprocessors: {
       'spec/javascripts/**/*.js': ['webpack', 'sourcemap'],
     },
-    reporters: [progressReporter, 'coverage-istanbul'],
-    coverageIstanbulReporter: {
+    reporters: [progressReporter],
+    webpack: webpackConfig,
+    webpackMiddleware: { stats: 'errors-only' },
+  };
+
+  if (process.env.BABEL_ENV === 'coverage' || process.env.NODE_ENV === 'coverage') {
+    karmaConfig.reporters.push('coverage-istanbul');
+    karmaConfig.coverageIstanbulReporter = {
       reports: ['html', 'text-summary'],
       dir: 'coverage-javascript/',
       subdir: '.',
       fixWebpackSourcePaths: true
-    },
-    webpack: webpackConfig,
-    webpackMiddleware: { stats: 'errors-only' },
-  });
+    };
+  }
+
+  config.set(karmaConfig);
 };