Reading the site's description of the video, it's more like "how languages like Haskell and Elm are informing the design of Javascript libraries like Redux". So it's not so much Elm and Haskell TEACHING "mainstream" JS (whatever that is) but one library merely taking hints from other programming domains that are relevant to the particular use case it's trying to cover.
On a podcast interview, the author of Redux mentions learning about Elm until later, so it's more like "some libraries have converged on similar design principles".
So, that's sort of true, but sort of not. Dan (author of Redux) has said that he read the Elm Architecture document before creating Redux, and didn't fully understand it. But he believes that it did influence the design of Redux.
> JAMISON: So had you played with or heard of ELM beforehand or did you just realize the parallels afterwards?
> DAN: Yeah. There's been this, I'm feeling guilty about it because I had this Twitter exchange with Evan. Evan was a bit uncomfortable with me not mentioning Elm as much as he thought I should. I felt that yeah, he's probably right because I read about Elm a few times before actually creating Redux. I'm not sure if… when you get inspired by something but don't fully understand it and later you kind of reproduce it but you don't really get this connection and you only get it later. So I think that's kind of what happened because I distinctly remember reading about ELM architecture but I was thrown out by the syntax, so I didn't fully understand what's going on there. Later after some initial iterations of Redux, Andrew Clark actually showed me how it's similar to Elm if we changed some things. We did change them.
> Yes, I have not actually played with Elm yet. I've seen other people playing with it. I've seen some demos but I have not actually played with it myself. I really want to but I'm stuck in maintaining and GitHub issues and I can't find the time. I don't know. Maybe I'm just afraid it's going to be so awesome that I'll just try the JavaScript development.
