React v0.14

React v0.14
facebook.github.io

I've been on 0.14-rc1 and my favorite feature so far is stateless function components. So much cleaner than class-based components.

One downside is that hot reloading doesn't work with it yet (AFAIK). Hopefully that will come soon now that 0.14 is officially released. (And I believe Dan is/was on vacation.)

Andrew Clark (core contributor to Redux and creator of Flummox) just released Recompose which provides powerful capabilities for stateless components: https://github.com/acdlite/recompose.

Some of the benefits of stateless function components as outlined in Recompose's readme:

* They prevent abuse of the setState() API, favoring props instead.

* They're simpler, and therefore less error-prone.

* They encourage the smart vs. dumb component pattern.

* They encourage code that is more reusable and modular.

* They discourage giant, complicated components that do too many things.

* In the future, they will allow React to make performance optimizations by avoiding unnecessary checks and memory allocations.

For example, if you display photos in a table, there is no state, but if you display photos with a carousel, then you have state as the current page, but these two components should otherwise have the same interface and implementation. Also in general the current selection and scroll position is state, albeit stored in the browser, so any UI component can potentially have state, even if it is only stored implicitly in the DOM objects.

What really matters is whether the component holds any state with "semantic" meaning or that needs to be persisted (like a date the user selected in a date picker) or whether all the state is "presentational" (like the month a date picker is showing).

What you should do in React is not hold any "semantic" state in components, unless it's a component that is solely designed for holding and managing such state (e.g. Relay container components, or a root App component).

EDIT: slightly reworded to be clearer and more correct, since having the same API interface regardless of statefulness is implicit in React

Since React is a semver project, from the website:

> How do I know when to release 1.0.0?

> If your software is being used in production, it should probably already be 1.0.0. If you have a stable API on which users have come to depend, you should be 1.0.0. If you're worrying a lot about backwards compatibility, you should probably already be 1.0.0.