Personally, I find direct Typescript interpretation to be one of the best features. Typescript is not necessarily a simple type system, but it is an expressive one:
- It has great type inference avoiding Java style codespam
- It has gradual typing, enabling "risky" type casts
- It has fully functional types, enabling the productivity and readability improvements from functions as data
- It is 10 seconds away from having dependent types
Typescript took most of the best programming language research from the past 20 years and popularized it in a way that actually makes js hackers more productive without getting too much in the way.
The only hard thing has been that js interpreters don't understand typescript, requiring an awkward transpilation step with weird symlinks and other hidden complexity that works 99% of the time, but wastes a lot of time when it doesn't work just right.
If Deno could just solve that, it would be a great improvement. If it's also faster (as claimed) that's even better. This article shows a lot of other ways in which small, simple improvements add up to a much better product.
Can't wait until it's production ready.