I've used Haxe in several production projects, and if I'm starting a new code-base from scratch I would pick it again. (I prefer type system, the cross-compilation options, and the meta programming)

But if you're migrating an existing code base, TypeScript has a more obvious path forward. Because TypeScript is a superset of JS, it means that all of the JS files in your project will be compiled by TypeScript as is. And you can add the extra typing information as you go, it doesn't have to be an "all or nothing" transition.

Compare to Haxe, where you have to create a separate *.hx file, with a slightly different syntax. You can either translate all of your code (a massive undertaking), or type external files as an `extern Class`, or just use `Dynamic` (equivalent of TypeScript's "any"). But all of these involve a little bit of work for every single part of your code base, so it's going to add up.