> the adoption of TypeScript would not have been as high if a sound type system is 100% guaranteed. This is disproved as the dart language is finally gaining po

> the adoption of TypeScript would not have been as high if a sound type system is 100% guaranteed. This is disproved as the dart language is finally gaining popularity as Flutter is now widely used. Soundness is a goal of the dart language which is discussed here. Look, I wish TS type system was sound too, but that's not a "proof", it's just a data point. TS doesn't have the same goals as Dart, there are lots of variables which aren't the same, so you can't just take Dart's approach and say "look I proved it". There are lots of popular languages with unsound type systems; Java for example. I don't know how you could have a criticism of TS without mentioning the lack of sum types. Yes, you can fake it by having an object with the same field name differentiated by a string constant, it's still not as nice as having first class support for sum types.