Also, what is the motivation for a Dart web front end?
Discussion
When rewriting some legacy applications about 10 years ago a group looked for a easy to adopt type safe language for the web. From what I recall Typescript wasn’t strong enough yet and Darts google relationship was reassuring.
I am not impressed with where we are, but hindsight’s 20/20.
In my experience TS offers better compile time check if all code are in TS. But the JS runtime can still cause problems. Lack of tagged union and not type safe JSON make me not like Dart.