https://medium.com/@alex.lew/the-translator-pattern-a-model-for-child-to-parent-communication-in-elm-f4bfaa1d3f98 https://medium.com/@alex.lew/the-translator-pa

https://medium.com/@alex.lew/the-translator-pattern-a-model-for-child-to-parent-communication-in-elm-f4bfaa1d3f98 https://medium.com/@alex.lew/the-translator-pattern-a-model-... describes the pattern quite well in elm-first terms.