I've used both. They're different monsters. Elm is a functional-first language and a reactive GUI framework all in one. Typescript is just a superset of JS.

I've used both. They're different monsters. Elm is a functional-first language and a reactive GUI framework all in one. Typescript is just a superset of JS. Elm is pretty neat if you want to build a reactive GUI framework with everything immutable by default and have lots of functional programming idioms at your disposal. However that's all it does: if you want to do e.g. server-side rendering or use it in an angular project you're out of luck; if you want to interop with other JS code then it's a pain. Typescript doesn't enforce any paradigm or bring any particular framework with it. It's just Javascript with type annotations and some extra features. So you can use it with React and Redux to create something like Elm's framework, but it won't be quite as safe or concise as you'd get with Elm. However it fits in much nicer with other JS libraries and can run on the server or alongside any JS GUI framework of your choice. Elm is also still officially beta, and new releases often involve fairly large breaking changes. Personally I started off a big fan of Elm but fell off the bandwagon as I ran into its limitations.