elm-ts VS purescript-concur-core

> By that time, TypeScript had grown to be capable enough (and developer-friendly enough) to balance much of what sold us on Elm originally: a usable type system, good-enough error messages, etc. React had baked in some more useful state management primitives that roughly matched Elm’s “batteries included” state management.

if you like the ideas in elm but don't want to commit to it I'd encourage you to check out elm-ts (https://gcanti.github.io/elm-ts/) It has a little bit more boilerplate than elm (I find elm to be quite verbose already!) but a better experience for individuals and teams overall, I would say. It's a good example of how "TypeScript had grown to be capable enough (and developer-friendly enough) to balance much of what sold us on Elm originally: a usable type system.."

FWIW this post is about PureScript, not Elm. The library is an implementation of the Elm Architecture in PureScript. Elm is a language. The framework that goes along with it is called "The Elm Architecture". The Architecture can be implemented in any language. Here's an implementation in TypeScript: https://github.com/gcanti/elm-ts

1. Application wide state is easy since you can always access state from parent components in child components. The problem occurs when you want to update parent state from child components.

Fortunately, you can make your own abstractions in Concur. For example, you can use a "Wire" - which lets multiple child components share and update parts of the parent's state (https://github.com/purescript-concur/purescript-concur-core/...). Note how this abstraction just uses the high level Concur API, and doesn't depend on the UI backend. With a wire the code might look something like this -

  -- A wire into parent's state, accessible using `with`, and updateable using `wire.send`

Have you looked at signals? AFAICT they are exactly what you are looking for. A signal is just Cofree widget (https://github.com/purescript-concur/purescript-concur-core/blob/master/src/Concur/Core/FRP.purs#L26).