The initial downloaded code for video 2 has multiple bugs

Among the bugs are:

1. Stopwatch:componentDidMount uses setInterval without a delay argument which doesn't seem well-documented by MDN and doesn't seem discussed much on the web. In Firefox (55) the timer fires once and stops rather than repeating
   • https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setInterval
   • https://developer.mozilla.org/en-US/Add-ons/Code_snippets/Timers
2. Stopwatch:getInitialState has a misspelled key previouseTime that wreaks havoc on the correct logic

Probably frustrating and difficult to troubleshoot for beginning learners

• When trying to get strange failures to work , it can be difficult to know what might be wrong
  • e.g. what if it is a browser cache problem because you can't seem to get the right code version in the browser
• they also have to remember to manually rebuild and re-serve the changed app at this point in the training