The thing with Typescript is that it is only a fancy JavaScript linter, so the only way to justify newer releases is to keep adding up the type system, there is nothing else when language features that aren't type system related are supposed to come from JavaScript evolution.
So they either say they are done, or keep adding type theory stuff until it implodes, I fear.
Actually I am looking forward to type annotations in JavaScript now in the roadmap, being good enough for general use cases.
Is there a more simple JS linter that does 90% of what basic TypeScript does? I mostly use simple types (basic times, Promises, arrays, and a bunch of interfaces) and I find TypeScript valuable for that. It saved me a few times from accidentally treating a Promise<Whatever> as Whatever for example – and other things.
But I heard an interesting argument: It's not TypeScript vs. vanilla JS; it is TypeScript vs. whatever else full-blown linting/IDE comfort you can get by still writing vanilla JS with no transpile step.
I don't have the source at hand but I remember seeing that they wouldn't support it until it had progressed as a JavaScript proposal. Their reasoning was that the decorations API is really weak, and it will likely be changed meaning a complete rewrite of the TypeScript decorator implementations.
So they either say they are done, or keep adding type theory stuff until it implodes, I fear.
Actually I am looking forward to type annotations in JavaScript now in the roadmap, being good enough for general use cases.