It was originally meant as a better JavaScript and it was. It failed when none of the other browsers expressed interest in supporting it. It languished for a while and then was taken up by the Flutter team. At the time Flutter took it up it was somewhere around the level of Java 8 in features but not quite on par. Since then it’s seen some massive improvements to the type system and language. It’s completely null sound, not just null safe like Kotlin. It recently got records/tuples and one of the more capable pattern matching syntaxes I’ve ever seen in a functional imperative hybrid language. The next stable version of dart will introduce a compiler macro system that is very promising. The syntax isn’t always the prettiest due to it trying to not totally break old code. I do think that it offers a wide range of modern language features that competes heavily with Swift and Kotlin in the mobile space.

Just had to look at it out of curiosity and man, it looks like yet another C+=1. The code samples on Wikipedia contain one of those gaudy for-loops and a ternary, as if that was still peak language design four decades after C got published.

But what I seriously don't get: Why the hell did they develop Go then? That's yet another C+=1, with even some design similarities to Dart, e.g. it's garbage-collected but compiles to machine code.
Like, yeah, it wouldn't be the first time that different teams develop competing products at Google, but what kind of culture leads to there even being demand for two C+=1s?