Implementing TDD for the Reactive Form in our calculator app

A reactive form is a type of form that uses reactive programming principles to update the form state in response to user input. Reactive forms are often used in web applications, as they can be used to create dynamic and responsive user interfaces.

In this section, we will discuss how to implement a reactive form user interface for our calculator app. We will use TDD to ensure that our form is valid and that our calculator component works as expected.

Here are the benefits of using a reactive form user interface for a calculator:

• Dynamic and responsive: Reactive forms can be used to create dynamic and responsive user interfaces. For example, you could use a reactive form to create a calculator that updates the result as the user enters values into the input fields.
• Valid: Reactive forms provide validation features that can be used to ensure that the user input is valid. For example, you could use a reactive...