[pmkary]

Not at all. Before the use of TypeScript exploded, they had two features brought into it from C# which were namespaces and enums (both of which are amazingly good features. For the first one, no one knew what was the right choice back then. We had almost a dozen different module systems and TypeScript had gone their way to support all of them and namespaces were their own solution to the mess (remember they were trying to solve their own problems at first, it wasn't to dominate anything). I personally used namespaces and I could have only the TypeScript compiler running and producing a single JS file for rapid development without the burden of --- then very slow --- webpack.

And for enums, using strings as enums was not a very efficient idea. I think JavaScript introduced Symbols for locked/hidden properties but also meant to use them as enums. It never worked either and then the sum type, union type feature of TypeScript made the whole community to keep using strings as enums. This is still a very bad idea, it is not ergonomic, it is prone to many problems, and very inefficient to compare strings instead of integers. But hey TypeScript tried to fix the problem and almost everyone rejected it. And so enum is now discontinued.

Rest of the changes to TypeScript came from almost any other language but C#, probably the biggest changes ever to happen to JavaScript came directly from CoffeeScript. And then I personally saw how each of these new changes --- one by one --- arrived at C#. For what I have seen firsthand by reading the TC39 proposals, each feature came from a different community and different programming languages, (think about null operators !/?, the nullish coalescing ??, the incoming pipes, fat arrows and lambdas, mixings) as JavaScript is the only language everyone has to use, and it has benefited everyone to have a language that has all the great things from all other languages.