Not able to use .ts files with Jasmine and Karma. Getting error 'Unable to determine file type..'

Question

I really need some help to configure karma.conf.js to handle typescript files or not sure what is missing or what I am doing wrong here. Pretty new to unit-testing and learned the Jasmine framework (in the examples it uses *.js and *.spec.js files) but in my ionic-angular project its *.ts files and getting errors (shown below). I have been trying to figure it out for 2 days and not able to get this solved. Any help really appreciated.

[Using ionic 3 (ionic-angular 3.9.+) framework with Angular 6 (6.1.10) and typescript (3.8.+.)]

my tsconfig.json >

 {
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "declaration": false,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "lib": [
      "dom",
      "es2015"
    ],
    "module": "es2015",
    "moduleResolution": "node",
    "sourceMap": true,
    "target": "es6"
  },
  "include": [
    "src/**/*.ts"
  ],
  "exclude": [
    "node_modules",
    "src/**/*.spec.ts",
    "src/**/__tests__/*.ts"
  ],
  "compileOnSave": false,
  "atom": {
    "rewriteTsconfig": false
  }
} 

my karma.conf.js >

module.exports = function (config) {
  config.set({
    frameworks: ['jasmine', 'jasmine-matchers'],
    files: [
      'src/**/*.ts',
      'src/**/*.spec.ts'
    ],
    plugins: [
      'karma-jasmine',
      'karma-jasmine-matchers',
      'karma-chrome-launcher'
    ],
    reporters: ['dots'],
    colors: true,
    browsers: ['ChromeHeadless'],
    singleRun: true
  })
};

my package.json devDependencies:

"devDependencies": {
    "@ionic/app-scripts": "3.2.4",
    "jasmine-core": "^3.5.0",
    "karma": "^5.1.0",
    "karma-chrome-launcher": "^3.1.0",
    "karma-jasmine": "^3.3.1",
    "karma-jasmine-matchers": "^4.0.2",
    "puppeteer": "^1.20.0",
    "ts-node": "^8.10.2",
    "typescript": "^3.8.3"
  },

ERROR I am getting:

15 06 2020 09:40:23.844:WARN [middleware:karma]: Unable to determine file type from the file extension, defaulting to js.
  To silence the warning specify a valid type for C:/Users/USR01/Documents/testing/src/providers/member/member.ts in the configuration file.
  See http://karma-runner.github.io/latest/config/files.html
........
........
15 06 2020 09:40:23.844:WARN [middleware:karma]: Unable to determine file type from the file extension, defaulting to js.
  To silence the warning specify a valid type for C:/Users/USR01/Documents/testing/src/providers/scores/scores.ts in the configuration file.
Chrome 83.0.4103.97 (Windows 10): Executed 0 of 0 SUCCESS (0.001 secs / 0 secs)
npm ERR! Test failed.  See above for more details.

Answer 1

This looks promising. https://www.npmjs.com/package/karma-typescript

Once you add a preprocessor to compile TypeScript to regular Javascript, tell Karma it is a js file by putting this in your files: [] array:

  files: [
    {
      pattern: 'src/**/*.ts',
      type: 'js'  // to silence the warning. Means load with <script> tag
    },
  ]