I used angular-cli create an Angular 2 app, use the default settings. Then I used ng serve command to start the server and made some changes. I must say the process is much better than before, which I has to change the package.json and set up a build tool, e.g. gulp or webpack, specially to enable live-reloading. Now angular-cli has all done that for me. Really sweet!

Then I left my desktop and stopped the build task. After I returned back and started to run ng serve again, I got an error.

The fix for this error is quite simple: change the generated spec.ts file. The reason I think is Broccoli is run the test spec files before it compile the file and feed them to system.js so that Angular can load them onto the webpage. But I was not using a TDD approach so the test file were not match with the app file. So Broccoli was failling.

It looks like Angular is promoting TDD approach!