Hyperapp can do something like this. You can have an action that sends a message for another action. This is how it handles asynchronous HTTP requests for insta

Hyperapp can do something like this. You can have an action that sends a message for another action. This is how it handles asynchronous HTTP requests for instance: the http() function takes both the URL/params for the request, and the name of an action that will receive the response as an argument. The result feels very Elm-like, albeit sans the assurances of the typing.