In many code learning sites, the application is able to test the code entered by user. Ex: freecodecamp.org runs unit tests to check if user has entered correct code. I am trying to get the same feature using angular as front end. I know that we can run tests from CLI using karma, but i want to run these tests when user inputs the code and show him if he as entered the expected code. I want to know how can it be done within the application.