(edit: red flag is a bad description, because he ended up being self-reflective and looking deeper, which is just about the furthest thing from a red flag.)
Then Java is a verbose language in general (forced directory structure, one-class-per-file and yadda yadda) but that's besides the point as you're pointing to TypeScripts types being less verbose than Javas.
2) TypeScript has type aliases, meaning you can write `type MyTable = List<Map<string, number | string | Foo>>` and not have to repeat yourself everywhere.
3) TypeScript has anonymous unions and tuples, so instead of writing `Triple<Integer, String, Foo>` you can just write `[number, string, Foo]`, and likewise instead of `OneOf<Integer, String, Foo>` you can write `number | string | Foo`. These are also built in and very ergonomic, so you don't have to write a OneOf4 class whenever you want to have one of 4 things, and you don't have to write helper methods to convert between different sized OneOfs.
But... teammates were running in to issues with 'new' stuff - like, using 'var'. There were others, but this was sort of the archetypal argument. "Well, it doesn't match the rest of the style of the file/app - it'll make it hard to read". Well... hrm... any new feature literally doesn't match the style of what came before it, because you have new keywords/features/syntax to handle processes a new way. It's definitional. But just because there's a new feature doesn't mean it'll be adopted (for better or worse, I supposed, depending on your stance).
(That part has also gotten better, but especially the Java 8 -> anything later upgrade has been extremely painful because of modularization. Past Java 9 it usually isn't that much of an issue. However, JDK 11 was the first LTS release after 8, so most shops basically delayed the transition until JDK 11.)
VerboseTypeName foo = new VerboseTypeName();It wasn't until I started using Haskell that I saw the benefits of knowing exactly what I was working with. It also helped me be more deliberate and thoughtful as you had to define everything up front.
No, red flag is fair since it's just a warning sign. Even if we take it as a mark on the guy, it's true that he ought to get outside the scripty bubble.