ReferenceError: Can't find variable: exports

Background: I have an AngularJS mixed with an Angular application, using the `ng-upgrade` module in order to make them live together.

So I have a mixing of `ts` and `js` inside the project and I am setting up karma in order to execute all the tests (`ts` and `js` ones).

When I execute karma and it parses the js files of the downgraded components, at the end of the js file I have an `exports` statement, as the following for example:

exports.registerDowngradedComponents = registerDowngradedComponents;

At that line, Karma gives me the following error:

> ReferenceError: Can't find variable: exports

Here is my relevant parts of `karma.config.js` file:

// Docs and references for karma-typescript:

// karma-typescript plugin:
// https://www.npmjs.com/package/karma-typescript
// karma-typescript AngularJS integration and sample:
// https://github.com/monounity/karma-typescript/tree/master/examples/angularjs
// karma-typescript Angular2 integration and sample:
// https://github.com/monounity/karma-typescript/tree/master/examples/angular2
// karma-typescript Gulp integration and sample:
// https://github.com/monounity/karma-typescript/tree/master/examples/gulp

var karmaTypescriptAngular2Transform = require('karma-typescript-angular2-transform');

// Karma configuration
// Generated on Tue Dec 23 2014 13:37:34 GMT+0000 (GMT Standard Time)

module.exports = function (config) {
config.set({

// base path that will be used to resolve all patterns (eg. files, exclude)
basePath: '',

// frameworks to use
// available frameworks: https://npmjs.org/browse/keyword/karma-adapter
frameworks: ['jasmine', 'karma-typescript'],

// list of files / patterns to load in the browser
files: [
'node_modules/babel-polyfill/dist/polyfill.js',

// ng2 stuffs
'node_modules/zone.js/dist/zone.js',
'node_modules/zone.js/dist/long-stack-trace-zone.js',
'node_modules/zone.js/dist/proxy.js',
'node_modules/zone.js/dist/sync-test.js',
'node_modules/zone.js/dist/jasmine-patch.js',
'node_modules/zone.js/dist/async-test.js',
'node_modules/zone.js/dist/fake-async-test.js',
'node_modules/reflect-metadata/Reflect.js',
'node_modules/systemjs/dist/system-polyfills.js',
'node_modules/systemjs/dist/system.js',

// ts definitions
'app/**/*.ts',

'spec/unit/stateMock.js',
// spec files
'app/**/*_spec.js',
'app/**/*_spec.ts',
// because views get compiled to templateCache
'app/**/*.html'
],

// all reporters and plugins have to be stated here
plugins: [
'karma-typescript',
'karma-coverage',
'karma-jasmine',
'karma-phantomjs-launcher',
'karma-chrome-launcher',
'karma-htmlfile-reporter',
'karma-junit-reporter',
'karma-ng-html2js-preprocessor'
],

// test results reporter to use
// possible values: 'dots', 'progress'
// available reporters: https://npmjs.org/browse/keyword/karma-reporter
reporters: ['progress', 'html', 'coverage', 'junit', 'karma-typescript'],

htmlReporter: {
outputFile: 'spec/reports/unit/unit_tests.html'
},

coverageReporter: {
type: 'html',
dir: 'spec/reports/coverage/',
reporters: [{
type: 'lcov',
subdir: 'lcov'
}, {
type: 'html',
subdir: 'report-html'
}, {
type: 'cobertura',
subdir: '.',
file: 'cobertura.xml'
}]
},

junitReporter: {
outputFile: 'spec/reports/unit/test-results.xml',
suite: ''
},

ngHtml2JsPreprocessor: {
moduleName: 'templates',
stripPrefix: 'app/'
},

preprocessors: {
'**/*.ts': ['karma-typescript'],
'app/**/!(*spec|*_spec).js': ['coverage'],
'app/**/*.html': ['ng-html2js'],
},

// start these browsers
// available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
browsers: ['PhantomJS'],

// TypeScript configuration specification with ng2 options too
karmaTypescriptConfig: {
tsconfig: './tsconfig.json',
bundlerOptions: {
entrypoints: /_spec\.ts$/,
transforms: [
karmaTypescriptAngular2Transform
]
},
compilerOptions: {
lib: ['ES2015', 'DOM']
}
}

});
};

Here my `tsconfig.json`:

{
"compilerOptions": {
"target": "es5",
"module": "commonjs",
"moduleResolution": "node",
"sourceMap": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"lib": [
"es2015",
"dom"
],
"noImplicitAny": true,
"suppressImplicitAnyIndexErrors": true,
"types": [
"angular",
"node",
"jasmine"
]
}
}

Any idea how to fix that please? I looked to all the questions quite related to it but no luck.

Any help would be really appreciated. Thanks.

Start with karma.config.js and tsconfig.json, especially the karma-typescript bundler settings and the listed JavaScript files for downgraded components. Run the Karma suite in PhantomJS and trace the failing exports statement; done means the mixed TypeScript and JavaScript tests execute without the ReferenceError.

Written by the indexing model from the issue text.