Why SPA (Single Page App)?

Question

Inspired by John Papa's video at Pluralsight, I started learning SPA. It appears pretty interesting. However, before I fully jump in, I'd like to clarify some of my questions.

1. From what I learnt, SPA is a lean server, fat client app. I think this should work well for small apps like what John Para demonstrated. Does it scale? How big it can be? Anybody has experience with this?

2. In SPA, you seem to code all the business logic in JavaScript. Is this a good idea at all? How do you hide the business "secret"?

With my background primarily in C#/WPF/.NET, moving to JavaScript seems to be very difficult (well, I learnt a little JavaScript more than 10 years ago - I hated it and never touched it again). With my limited knowledge, I ran into several problems. Debugging JavaScript seems to be a nightmare to me. The highly praised component Breezejs seems to be still in its early stage (e.g. it doesn't support UOW, doesn't support CascadeDelete, doesn't support enums). So, I'm wondering this is good time to jump in?

Answer 1

Directly to your questions:

1. Since the server logic is thin you can use some kind of cloud services and they scale pretty good. The most of the logic will be handled by the browsers of your users.
2. You should be careful if you depend on client. HTTP protocol can be easily manipulated. Don't forget that you should always do the validation logic both on client and server side! Also the "hidden" validation and other "secret" logic should be located only on the server.

Debugging JavaScript isn't so bad at all. You can use the built-in tools (Inspect element in Chrome and FireBug in Firefox, etc.) Also there are a lot of useful third party tools that will help you with the debugging.

If you start a new project just for your own use then I advice you to try the SPA approach. If you are writing production code you should become an expert in this area and then try to use these technologies.