diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7d0c976d816..b8619d7d3f8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -254,7 +254,7 @@ karma:
     name: coverage-javascript
     expire_in: 31d
     paths:
-    - coverage-javascript/default/
+    - coverage-javascript/
 
 lint-doc:
   stage: test
@@ -393,7 +393,7 @@ pages:
     - mv public/ .public/
     - mkdir public/
     - mv coverage/ public/coverage-ruby/ || true
-    - mv coverage-javascript/default/ public/coverage-javascript/ || true
+    - mv coverage-javascript/ public/coverage-javascript/ || true
     - mv eslint-report.html public/ || true
   artifacts:
     paths:
diff --git a/changelogs/unreleased/cover-my-karma.yml b/changelogs/unreleased/cover-my-karma.yml
new file mode 100644
index 00000000000..4a823dc5ca4
--- /dev/null
+++ b/changelogs/unreleased/cover-my-karma.yml
@@ -0,0 +1,4 @@
+---
+title: Reintroduce coverage report for JavaScript
+merge_request: 9133
+author: winniehell
diff --git a/config/karma.config.js b/config/karma.config.js
index 44229e2ee88..a1fbeab1f46 100644
--- a/config/karma.config.js
+++ b/config/karma.config.js
@@ -15,6 +15,13 @@ module.exports = function(config) {
     preprocessors: {
       'spec/javascripts/**/*.js?(.es6)': ['webpack', 'sourcemap'],
     },
+    reporters: ['progress', 'coverage-istanbul'],
+    coverageIstanbulReporter: {
+      reports: ['html', 'text-summary'],
+      dir: 'coverage-javascript/',
+      subdir: '.',
+      fixWebpackSourcePaths: true
+    },
     webpack: webpackConfig,
     webpackMiddleware: { stats: 'errors-only' },
   });
diff --git a/config/webpack.config.js b/config/webpack.config.js
index 2ac779c8511..5d5e4bb570a 100644
--- a/config/webpack.config.js
+++ b/config/webpack.config.js
@@ -54,6 +54,7 @@ var config = {
         exclude: /(node_modules|vendor\/assets)/,
         loader: 'babel-loader',
         options: {
+          plugins: ['istanbul'],
           presets: [
             ["es2015", {"modules": false}],
             'stage-2'
diff --git a/package.json b/package.json
index 48f571eda9b..0500ba9670e 100644
--- a/package.json
+++ b/package.json
@@ -37,6 +37,7 @@
     "webpack-dev-server": "^2.3.0"
   },
   "devDependencies": {
+    "babel-plugin-istanbul": "^4.0.0",
     "eslint": "^3.10.1",
     "eslint-config-airbnb-base": "^10.0.1",
     "eslint-import-resolver-webpack": "^0.8.1",
@@ -47,9 +48,18 @@
     "jasmine-core": "^2.5.2",
     "jasmine-jquery": "^2.1.1",
     "karma": "^1.4.1",
+    "karma-coverage-istanbul-reporter": "^0.2.0",
     "karma-jasmine": "^1.1.0",
     "karma-phantomjs-launcher": "^1.0.2",
     "karma-sourcemap-loader": "^0.3.7",
     "karma-webpack": "^2.0.2"
+  },
+  "nyc": {
+    "exclude": [
+      "spec/javascripts/test_bundle.js",
+      "spec/javascripts/**/*_spec.js",
+      "spec/javascripts/**/*_spec.js.es6",
+      "app/assets/javascripts/droplab/**/*"
+    ]
   }
 }
diff --git a/spec/javascripts/test_bundle.js b/spec/javascripts/test_bundle.js
index 030d2de090a..ca707d872a4 100644
--- a/spec/javascripts/test_bundle.js
+++ b/spec/javascripts/test_bundle.js
@@ -42,3 +42,38 @@ testsContext.keys().forEach(function (path) {
     });
   }
 });
+
+// workaround: include all source files to find files with 0% coverage
+// see also https://github.com/deepsweet/istanbul-instrumenter-loader/issues/15
+describe('Uncovered files', function () {
+  // the following files throw errors because of undefined variables
+  const troubleMakers = [
+    './blob_edit/blob_edit_bundle.js',
+    './cycle_analytics/components/stage_plan_component.js',
+    './cycle_analytics/components/stage_staging_component.js',
+    './cycle_analytics/components/stage_test_component.js',
+    './diff_notes/components/jump_to_discussion.js',
+    './diff_notes/components/resolve_count.js',
+    './merge_conflicts/components/inline_conflict_lines.js',
+    './merge_conflicts/components/parallel_conflict_lines.js',
+    './network/branch_graph.js',
+  ];
+
+  const sourceFiles = require.context('~', true, /^\.\/(?!application\.js).*\.(js|es6)$/);
+  sourceFiles.keys().forEach(function (path) {
+    // ignore if there is a matching spec file
+    if (testsContext.keys().indexOf(`${path.replace(/\.js(\.es6)?$/, '')}_spec`) > -1) {
+      return;
+    }
+
+    it(`includes '${path}'`, function () {
+      try {
+        sourceFiles(path);
+      } catch (err) {
+        if (troubleMakers.indexOf(path) === -1) {
+          expect(err).toBeNull();
+        }
+      }
+    });
+  });
+});