I second this suggestion. I'm a backend developer(barely, mostly a sysadmin who happens to write Go backends for various reasons). I wanted to learn some frontend because I wanted to make some internal pages for my users. I tried React, but found the API surface I needed to learn to be productive overwhelming.

I tried Elm on a whim, and found it very focused on being productive. Functional programming was very new to me, but I spent a weekend with https://pragmaticstudio.com/courses/elm and it was enough to get me started.

The Elm Guide(http://guide.elm-lang.org/) and Elm Slack http://elmlang.herokuapp.com/ are both fantastic resources for learning the language.