What We Learned

The things you learned in this chapter are certainly not basic tools. On the other hand, software developers don’t work on basic applications. Each one is its own unique case, and I hope that the two techniques covered in this chapter will help you wrangle the difficult edge cases that reality inflicts upon our work.

When your application starts slowing to a crawl, you can measure exactly what “a crawl” means. Once you’ve measured, it’s time to break out observables and OnPush to optimize Angular’s change detection passes.

On the other hand, you’ve also learned about ngrx and state management. Most software bugs are due to an application’s state being set to something that was not intended. Interestingly, this is why “turn it off and on again” works, it resets the state. Rather than constantly asking users to refresh the page, you can now kill those bugs before they even spawn, taming the wild beast of state through reducers.

While Angular provides a solid, RxJS-powered backbone for framing your apps, you don’t need Angular to use RxJS in a modern web application.
If you want to learn more about using RxJS for state management in an Angular application, here’s a challenge for you. In the previous few lessons, the ngrx covered was creating, reading, and updating patient data. What we didn’t cover was deleting. What needs to be done to add an event to remove a patient from the full list of patients?