Are they pure? I don't think JS has any way to guarantee referential transparency, though of course the use of a virtual DOM can mitigate side effects by having well-defined behavior.
Furthermore, the input-process-output model can hardly warrant being called "functional" in of itself, unless you really want to overload the term.
The React way of independent handlers that trigger events which incrementally calculate state and update views, is, in fact, quite similar to how Smalltalk UI paradigms work, right down to the installation of an event handler resembling a message send operation.
Furthermore, the input-process-output model can hardly warrant being called "functional" in of itself, unless you really want to overload the term.
The React way of independent handlers that trigger events which incrementally calculate state and update views, is, in fact, quite similar to how Smalltalk UI paradigms work, right down to the installation of an event handler resembling a message send operation.
If you don't believe me, check out the Morphic framework that Self uses to implement its environment UI. The similarities are striking: http://handbook.selflanguage.org/current/morphic.html