TypeScript: Modern JavaScript Development

Test spies and stubs with Sinon.JS

We have been working on the MathDemo class. We have implemented and tested its features using unit tests and assertions. Now we are going to create a little web widget that will internally use the MathDemo class to perform a mathematical operation. We can think of this new class as a graphical user interface for the MathDemo class. We need the following HTML:

<div id="widget">
  <input type="text" id="base" />
  <input type="text" id="exponent" />
  <input type="text" id="result" />
  <button id="submit" type="submit">Submit</button>
</div>

Note

In the companion code, the HTML code contains more attributes, such as CSS classes; but they been have removed here for clarity.

Let's create a file named calculator_widget.ts under ...