Stopwatch

A countdown timer with 'start', 'pause' and 'reset' functionality.

We'll cover the following...

Exercise:

Create a stopwatch that counts down from a given number of seconds in the format mm:ss. Make it possible to start, pause, and reset the countdown. Make sure you can pass a callback function to the timer that is called when the displayed value is updated.

Solution:

The main part of this exercise boils down to modeling. If you find the right model, your life will be easy. If you use the wrong model, implementation will ...