When you are building even moderately large non-trivial real world software with JS, you would thank your stars that TS exists and that it has features like this. It's amazing how quickly the basic concepts of software engineering become inadequate when they run up against the real world.

For example, a naive engineer might think, ah, databases have this oFFSET clause, good, I'll use, unaware that is a foot gun for real world performance.

Or they may think the DELETE operation on DBs is a normal thing, unaware that in most cases it should NOT be used at all.

Or they might think loops are idiomatic, unaware that when you are writing large software you should and can probably almost eliminate loops (unless you are using a DSL like SQL extensions, config languages, etc)

Or they may be unaware of the thorny issues around queues (or even why they might be necessary in the first place) and concurrent access to data.

Or they might not understand why the dogma of separating content and presentation is nonsensical in many situations.

Etc.

I think this is spot on. TS goes very very far without the gymnastics. Its good to know these things, but not even close to necessary to be productive. Not to mention IDE support for TS is on a very different level conpared to the shitshow that is Javascript.

Also, Angular dev spotted :)

You can do that with assembly and not know ANY high level language.

You might be interested in reading PG's treatise on "the blub paradox".

Can you even do that? I though you could only enterprise in secure languages, like Java