Webpack Karma Istanbul Remapping for TypeScript

Question

I'm developing a client-side app and I'm having trouble with creating the right Karma configs. Right now, I have my setup as follows:

Webpack: Using ts-loader, compiles TypeScript, assets etc.

Karma: Using the webpack plugin, loads the Webpack config (which uses ts-loader), then runs all unit tests with Jasmine + PhantomJS

The unit tests all run fine, but I haven't figured out a way to handle the webpack istanbul remapping. Karma-webpacks seems to not be generating source maps to allow the remapping to happen. Any pointers would be appreciated!

Karma Config:

var webpackConfig = require("./webpack.config.js");
delete webpackConfig.entry;

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'],

        // list of files / patterns to load in the browser
        files: [
            // Non-automatically bundled libraries
            'app/client/js/lib/easeljs.min.js',
            'app/client/js/lib/tweenjs.min.js',
            // Entry File
            'app/client/js/index.ts',
            'app/client/html/**/*.html',

            // Test files and dependencies
            'node_modules/angular-mocks/angular-mocks.js',
            'test/client/**/*.spec.js'
        ],

        // preprocess matching files before serving them to the browser
        // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
        preprocessors: {
            '**/*.html': ['ng-html2js'],
            'app/client/js/index.ts': ['webpack', 'sourcemap', 'coverage']
        },

        ngHtml2JsPreprocessor: {
            cacheIdFromPath: function (filepath) {
                // Remaps the path for Karma webpack
                return '/_karma_webpack_//' + filepath.replace(/^.*[\\\/]/, '');
            },
            moduleName: 'templates'
        },

        webpack: webpackConfig,

        webpackMiddleware: {
            noInfo: true
        },

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

        coverageReporter: {
            dir: 'build/client/test/coverage/',
            reporters: [
                {
                    type: 'json',
                    subdir: '.'
                }
            ]
        },

        // web server port
        port: 9876,

        // enable / disable colors in the output (reporters and logs)
        colors: true,

        // level of logging
        // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
        logLevel: config.LOG_INFO,

        // enable / disable watching file and executing tests whenever any file changes
        autoWatch: true,

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

        // Concurrency level
        // how many browser should be started simultaneously
        concurrency: Infinity
    })
};

Answer 1

Currently Karma Remap Istanbul is the only package capable of generating TypeScript coverage inline. It can also obviously be managed by simply calling remap-istanbul on your generated coverage.json.

This package will get you TypeScript coverage output summary on the console assuming you set the output config to text: undefined

Adding it to your existing workflow is simple enough, the documentation on how exactly to do so in the packages github README.md.

Answer 2

Install karma-typescript:

npm install karma-typescript --save-dev

Put this in your karma.conf.js:

frameworks: ["jasmine", "karma-typescript"],

files: [
    { pattern: "src/**/*.ts" }
],

preprocessors: {
    "**/*.ts": ["karma-typescript"]
},

reporters: ["progress", "karma-typescript"],

browsers: ["Chrome"]

This will run your Typescript unit tests on the fly and generate Istanbul html coverage that look like this:

This eliminates the need for using Karma and webpack together, Karma is used for running the tests and creating coverage, webpack is used for bundling.