Changelog

Upcoming

Reagent no longer bundles React. Instead it uses cljsjs/react as a dependency. This means that you should no longer specify React in :preamble in your project.clj.
cursor is re-written, to be more efficient and flexible.
render now forces a deep update of all components, to make it more convenient to use with e.g. figwheel.
Renamed as-component to as-element, to match React's new terminology better (old name still works, though, for backward compatiblity).
Stop wrapping native components. This reduces the number of components created a lot, and can speed some things up substantially (especially render-to-string, that is not bound by browser performance). This is made possible by a new way of keeping track of which order to re-render dirty components.
Added create-element to make it easier to embed native React components in Reagent ones.
Arguments to components are now compared using simple =, instead of the old, rather complicated heuristics. NOTE: This means all arguments to a component function must be comparable with = (which means that they cannot be for example infinite seqs).
React updated to 0.12.1. Reagent now creates all React components using React.createElement.
render-component is now render, and render-component-to-string is render-to-string, in order to match React 0.12.1 (but the old names still work).
Add render-to-static-markup. This works exactly like render-to-string, except that it doesn't produce data-react-id etc.

Made Reagent compatible with ClojureScript 0.0-2173. reagent.core/atom now implements the necessary IAtom, ISwap and IReset protocols. Reagent should still be compatible with older ClojureScript versions, but you will get a lot of compilation warnings.

Breaking change: Component functions can get arbitrary arguments, and not just vectors and maps. This is a breaking change, but behaviour is unchanged if you pass a map as the first argument (as in all the examples in the old documentation).
React updated to 0.9.0.
You can now use any object that satisfies ifn? as a component function, and not just plain functions. That includes functions defined with deftype, defrecord, etc, as well as collections like maps.
reagent.core/set-state and reagent.core/replace-state are now implemented using a reagent.core/atom, and are consequently async.
Keys associated with items in a seq (e.g ”dynamic children” in React parlance) can now be specified with meta-data, as well as with a :key item in the first parameter as before. In other words, these two forms are now equivalent: ^{:key foo} [:li bar] and [:li {:key foo} bar].
Performance has been improved. For example, there is now practically no overhead for tracking derefs in components that don’t use atoms. Allocations and memory use have also been reduced.
Intro and examples have been tweaked a little to take advantage of the new calling conventions.

Changes in application state are now rendered asynchronously, using requestAnimationFrame.
Reagent now does proper batching of updates corresponding to changed atoms, i.e parents are rendered before children, and children are only re-rendered once.
Add reagent.core/flush to render changes immediately.
Bugfix: Allow dynamic id with hiccup-style class names.