karma.config.js

const {
  NodeModulesPolyfillPlugin,
} = require('@esbuild-plugins/node-modules-polyfill');

module.exports = config => {
  config.set({
    // base path that will be used to resolve all patterns (eg. files, exclude)
    basePath: '',

    // frameworks to use
    // available frameworks: https://www.npmjs.com/search?q=keywords:karma-adapter
    frameworks: ['jasmine', 'jasmine-matchers'],

    // list of files / patterns to exclude
    exclude: [],

    // preprocess matching files before serving them to the browser
    // available preprocessors: https://www.npmjs.com/search?q=keywords:karma-preprocessor
    preprocessors: {
      '**/*.ts': ['esbuild'],
    },

    esbuild: {
      logLevel: 'error',
      // This is needed to support `util.inspect()` usage in custom
      // `toEqualWithHash` matcher (defined in `setup.ts`)
      plugins: [NodeModulesPolyfillPlugin()],
      keepNames: true,
    },

    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: https://www.npmjs.com/search?q=keywords:karma-reporter
    reporters: ['mocha'],

    // 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: false,

    // start these browsers
    // available browser launchers: https://www.npmjs.com/search?q=keywords:karma-launcher
    browsers: ['ChromeHeadless'],

    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: true,

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