karma-remap-istanbul

Call remap-istanbul as a karma reporter, enabling remapped reports on watch

installation

Install karma-remap-istanbul as a dev-dependency in your project.

npm install karma-remap-istanbul --save-dev

configuration

Add the plugin, reporter and reporter configuration in your karma.conf.js.

{
  plugins: ['karma-remap-istanbul'],
  reporters: ['progress', 'karma-remap-istanbul'],
  remapIstanbulReporter: {
    reports: {
      lcovonly: 'path/to/output/coverage/lcov.info',
      html: 'path/to/output/html/report'
    }
  }
}

Example configuration with karma-coverage

{
  preprocessors: {
    'build/**/!(*spec).js': ['coverage']
  },
  plugins: ['karma-remap-istanbul', 'karma-coverage'],
  reporters: ['progress', 'coverage', 'karma-remap-istanbul'],
  remapIstanbulReporter: {
    reports: {
      html: 'coverage'
    }
  }
}

You will need to either install karma-coverage and configure it as a preprocessor for your transpiled modules under test or instrument the modules under test as part of your build process. If the latter option is chosen, the coverage statistics will need to be stored at the __coverage__ global variable (istanbul's default) or karma will not transmit them back to the runner.