I wouldn’t say React is “hacked together”. Perhaps you are referring to the React ecosystem? Facebook doesn’t build single-page apps with React, so naturally it doesn’t provide solutions for routing and similar concerns, so there is more churn as people are figuring this out together.

Isn't https://messenger.com a SPA?

Could you expand more on "Facebook doesn't build single-page apps in React"? I hadn't heard that before.

Like, facebook.com isn't one big single-page React app. They use it for specific pages/features.

Wait, do people use React for non-SPA websites?

I use React all the time for individual components on server-rendered pages. It feels like a natural extension to formerly monolithic Rails/Node/etc apps.

That said, when an SPA is called for I'd far rather use Ember and get routing, state and a hundred other things for free, without needing to bolt together an entire front-end framework from parts each time.

Of course, hence the focus on server-side rendering. It is quite difficult to do properly though. Facebook itself is not a single page application.

Yep! I find myself using React.js for complex forms/wizards on non-SPA websites far more often than using it to build SPAs.

Absolutely! I'm current using it for a entirely back-end routed Symfony app. It's perfect for any front-end stuff complex enough that jQuery would become a mess.

I completely disagree. Vue seems like a step backwards for me -- it does very little that I couldn't do with Backbone/Marionette. I don't want templates, I don't want data-binding, and I DEFINITELY don't want opaque directives in my HTML.