https://typing.io/ This is pretty similar I think, used in the past. Can use your own code with the paying/subscription

Hello -- I'm glad you like it! I believe typing.io has something like this, but for programming languages.

Or to improve your code writing speed and syntax familiarity; it would have to be integrated into your editor/IDE and tooling though, since I find that in some cases it helps a bit with productivity (autocomplete, auto-close, auto-format, etc).

https://en.wikipedia.org/wiki/Compute!

(It says they quit doing the type-in programs after 1988)

That’s exactly how I learned to code. Retyping code from Byte magazine, Dr. Dobbs, and Apple Incider.

Second that method.

It also increased my debugging skills as well when I entered one or more typos along the way.

Also works for human languages!

yes, instead of learning dart, you will be tasked with writing microsoft excel in dart