FormGroup with validators in Angular
Angular interview exercise on Forms, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
LoginComponent: a form with `email` (required, a valid email) and `password` (required, at least 8 characters). The submit button is disabled while invalid. After a blur, show <small class="error"> under a field that is invalid ("Enter a valid email" / "At least 8 characters"). Submitting sets `welcome` to "Welcome, <email>".
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.