This has been my experience with AngularJS 1 and TypeScript as well. Looks like there's at least some support for it (Quote the link: You get autocompletion hin

This has been my experience with AngularJS 1 and TypeScript as well. Looks like there's at least some support for it (Quote the link: You get autocompletion hints and type-checking as you're writing components, even in expressions inside markup). Not sure if it does things like restrict `value` to `input` elements or anything, or if it's just the expressions in the template.