Starting Angular 11, the karma-coverage-istanbul-reporter has been deprecated. In order to solve this, you can use karma-coverage.

In order to configure this, please do the following:

  1. Install the karma-coverage package - npm install karma karma-coverage

  2. Update the karma.conf.js file and modify the coverageIstanbulReporter to coverageReporter and use the type: 'json' find below an example of such a reporter configuration

    coverageReporter: {
      dir: 'build/reports/coverage',
      reporters: [
        { type: 'json', subdir: 'report-json' }
      ]
    },
    CODE