A simple UI programming pattern, with a circular, unidirectional data flow. It is very rigid by design, to be side-effect free, functional, unidirectional:

https://guide.elm-lang.org/architecture/

I'm no frontend guy, but I think it did/was inspire(d) react (redux?) maybe. Corrections on this very welcome

Yes it was too rigid. Too much boiler plate. The design space of functional UI is still being explored.

Correct - Elm was one of several inspirations for Redux:

- https://redux.js.org/understanding/history-and-design/prior-...