I agree with that but the way I see it is that if your JS code is bad, then you may get value out of TS, but if your JS code is already good, you won't get any value out of TS.
TypeScript is like training wheels on a bike. All good if your priority is not to fall, but if you want to compete in the Olympics, you may have different priorities.
Also, I think starting with JavaScript and migrating to TypeScript leads to much better code than just starting with TypeScript. I think the reason is because if you start with JavaScript, you naturally tend to avoid architectural complexity because it can quickly become unmanageable. So then when you add type annotations to existing JS code, you're not adding extra architectural complexity; just adding types.
When you start directly with TypeScript, it allows you to reason about much more complex interfaces so there is more temptation to over-engineer architecturally. Devs feel more free to invent all sorts of unnecessary abstractions which will come back to bite them later.
Spaghetti code is spaghetti code; you can label each noodle but it's still spaghetti.
> ... the way I see it is that if your JS code is bad, then you may get value out of TS, but if your JS code is already good, you won't get any value out of TS.
You might not get any value from the typing when writing the code, but the poor sod tasked with maintaining it two years later definitely will.
Also, the added types and compile time check will greatly benefit anyone trying to perform all but the most trivial of code refactoring.
Typescript adds some inertia initially, and you are correct in that it will allow inexperienced developers getting away with writing overly complex code, but it's definitely worth it for any code base larger than a couple thousand LoC.
It also lets experienced developers who are inexperienced with the code base become productive faster. It's a boon for anyone who hasn't been there since the start.
TypeScript is like training wheels on a bike. All good if your priority is not to fall, but if you want to compete in the Olympics, you may have different priorities.
Also, I think starting with JavaScript and migrating to TypeScript leads to much better code than just starting with TypeScript. I think the reason is because if you start with JavaScript, you naturally tend to avoid architectural complexity because it can quickly become unmanageable. So then when you add type annotations to existing JS code, you're not adding extra architectural complexity; just adding types.
When you start directly with TypeScript, it allows you to reason about much more complex interfaces so there is more temptation to over-engineer architecturally. Devs feel more free to invent all sorts of unnecessary abstractions which will come back to bite them later.
Spaghetti code is spaghetti code; you can label each noodle but it's still spaghetti.