Angular 2 versus React

Poylmer doesn't simplify UI development like React does, the components have to be statefully managed, and always will be because creating/destroying polymer/web components is expensive. The beauty of virtualdom is the previous state doesn't matter in deciding what the new UI should look like, or if a component should be added/removed. Simply render off the current state, which is cheap, and then the previous & current virtualdom is diff'd and applied to the real DOM.

Web components are exciting, and React can leverage it to do CSS sandboxing, though people are already effectively doing this [1]. And the cool thing with declarative programming is we can swap out implementations with more performant ones.

[1] https://github.com/gajus/react-css-modules

There is a strong argument against doing what JSX does in moving the HTML to JS - you allow developers to fall into the trap of creating complex conditional DOM that is hard to read without a disciplined team (if statements all over the place with imperative DOM construction for example). Neither approach of JSX or Angular's templating (or any other similar system to either) are without its warts, and this falls into an opinion discussion without real winners excepting for however a particular team prefers their templating.

One thing that wasn't discussed but that may come into play - the performance numbers out there for Angular 2 currently is extremely impressive. Optimized Angular 2 code is generally performing at about 2x the rate of other frameworks/libraries out there for UI rendering/repainting, and unoptimized Angular 2 code is performing at roughly the same parity as optimized React code (although optimized/unoptimized React code performs very similarly in many situations, which is a huge benefit of React).

I'm personally on the Angular side of the fence, I prefer the more declarative style to avoid the imperative DOM construction, but I could work with either (and have worked/am working with both) if they are done right. Both are impressive libraries though, and both have strong merits - at the end of the day, it comes down to how your team works, and what they're productive with. Both libraries are bringing excellent changes to how we do things in the frontend...I just wish tooling was there in maturity, that seems to be the greater pain point currently.

React's greatest strength is also its greatest weakness. It requires devs to compose their app out of multiple de-centralized parts. See 'javascript fatigue'.

If your aim is to write an isomorphic React app, you CAN"T just use 'plain old javascript' or anything that touches the DOM. If you care about SEO, this is a very important implementation detail to consider.

Angular2's greatest strength is also its greatest weakness. It provides a unified API for building apps. It forces you to do things the 'angular way' which is no different from Angular1.

So far Angular2 is heavily biased toward Typescript because it was written in TS and it was literally just released to beta 2 weeks ago. TS is good for devs bridging over from strongly-typed OOP languages, and TS provides better support for autocomplete in IDEs. TS is bad because it's not an 'official' standard and it may be an awkward transition for existing JS devs.

TS is not required, I have been writing an Angular2 app in strictly ES6 despite the lack of documentation/support.

Both: require transpilation; use observables (ie redux vs rxjs); use a HTML-like templating language for data binding; use the virtual DOM to speed up rendering; discourage mutating the DOM directly to encourage rendering on other platforms (ie mobile, isomorphic); require platform-specific shims that don't touch the DOM; etc...

The underlying technologies of both are more similar than different. React favors a more decentralized architecture. Angular2 favors a more monolithic architecture.

/axegrinding

Angular2 doesn't. Like React it uses a HTML-like templating syntax to generate views. Nothing is mixed in Angular2, everything is defined in JS and rendered as HTML.