Why I am moving to Angular 2 from AngularJS

I started poking into core Angular 2 concepts a few weeks ago and it has been a pleasant experience so far. I rewrote a bare-bones replica of an Angular 1 app that took me months in about 2 or 3 weeks. Although rewrites are typically faster due to familiarity, it was impressive seeing built-in support for most of the painful areas of Angular.

Yes, there is some cost due to the absence of backwards compatibility but hey, you can’t have it all. If you are thinking of choosing between Angular 1 or Angular 2, I’ll say go for Angular 2; it’s totally worth it. However, if you already have an Angular 1 app, then you should evaluate the ROI and impact of the move on your team and delivery schedules.

1. Simplicity

Both frameworks have steep learning curves, however I believe Angular 2 tries to simplify most of the confusing concepts of Angular 1.

The various derivatives of the $provider (value, constant, factory, service and provider itself) are all gone – everything is just a service now. The same applies to the scope, the powerful but hard-to-manage feature has been eliminated.

Error messages are much clearer and vector you faster into the root cause unlike Angular 1 which had some error messages that had to be ‘learnt’ over time for root-cause correlation.

The move to components, services and established modules and routes makes it easier to design and create components.

2. Better Tooling

Angular-cli is a great tool that reminds me of the ember-cli; it’s great that the Angular team finally provided first-class support for this. The cli is amazing, apart from the staples of project scaffolding, testing (unit + E2E) and linting; there is also support for pushing to Github (will even create a repo for you!), proxying and build targets. Big wins!!

 Augury worked well for me out of the box; I remember dropping batarang after running into lots of problems.

Codelyzer is another great tool that helps you to write consistent code conforming to your style guidelines across teams.

3. Typescript

Typescript is the main language for Angular 2 although there is support for JavaScript and Dart. This should hopefully make it more amenable to larger enterprises for adoption.

JavaScript can be difficult to manage at scale; I guess this is something that affects all weakly typed languages. Refactoring can be a big pain if you have to rename some module in a 100,000 line codebase. Quickly becomes a pain point and hard to do well. Static typing does help in that case.

4. Reactive Programming

Angular 2 is built with reactive programming in mind. It bundles Rxjs, part of the reactive extensions library which pushes you to use Observables and all the reactive goodness.

It can be challenging wrapping your head around functional reactive programming. Simply said, you need to understand the 5 building blocks of functional programming – map, reduce, zip, flatten and filter. With these, you can compose and combine various programming solutions. Hadoop is just a ramped up version of mapReduce.  The framework’s support for reactive concepts (e.g. observables) is deeply ingrained in a wide variety of places: routing, http and templates.

They is also support for promises but I think mixing Promises and Streams would lead to confusion. Choose one style and stick to it.

Want to learn more about streams? Check out my stream library and accompanying blog post.

5. Routing

Route guards, resolvers, router-link directives and more are a pure delight. Support for modular component routing is impressive too; this allows modules to have independent routing. So you can just pluck them out if you don’t need them anymore.

Angular 1’s routing was difficult to use because it was at the global level. Yes there were other routing implementations (proof to Angular’s extensibility) that helped with things like having multiple outlets in a page.

The good thing about angular 2 is that all these is built-in and that means you can easily implement a consistent approach to routing in all your app.

6. Modularity

Angular 2 comes with better modularity; you can declare modular blocks and use them to compose your application.

Angular 2 allows you to define components that control their routing, layout, sub-component make up and more. Imagine you are creating some web application to monitor social media platforms. I would imagine you’d have top-level navigation tabs for things like Facebook, Twitter and LinkedIn.

It’s possible to define each of these three as top-level modules on their own and then register them in the core app. So the Facebook module ideally should be able to handle its own routing, component and styling and more separately from the Twitter module. An extra benefit is that; you can take this module and re-use it in some other totally different project! That’s simply awesome.

Conclusion

Angular 2 is still new and though it’s been out there for some time; there is still a concern about how it would ‘perform’ at scale. The good thing though is that it handles most of the issues with Angular 1 really well.

Sure, there might be issues in the future but at least they would be new mistakes :)