Union types are a gap, although records and switch expressions will get you much closer than was previously possible.

Object literals are a thing, they’re called anonymous types. You just new them up. And functions can be passed around as first class objects, with some minor type boilerplate in a few places.

There are a few places where you have to adjust to different naming conventions and types are obviously stricter but my experience is that for the most part modern c# has all the things I like about TS/JS.

It is worth mentioning the c# team is taking a serious look at Union types finally. Considering the runtime already has a version in f# I'm curious how it goes on the c# side of the house (I know semantics are different between the two languages so can't necessarily be 1:1)

> Union types

Yes, these are missing in C#.

> Object literals

You could use records[1], or anonymous types[2].

> Functions as first class citizens

There's delegates[3] and lambda expressions[4]. Is there anything that's missing here that you need?

You can use lambda expressions almost exactly like you might in JS/TS, even omitting the type:

  var squared = x => x * x; 

And if you want even more functional, you could always use F#.

[1]: https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...

[2]: https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals...

[3]: https://learn.microsoft.com/en-us/dotnet/api/system?view=net...

[4]: https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...

> You could use records[1], or anonymous types[2].

Not quite with directness of JS.

> There's delegates[3] and lambda expressions[4].

Again you can get something equivalent, but not without some ceremony. It’s not as frictionless as with JS.

> It’s not as frictionless as with JS.

I'm not sure how much less friction you want than directly declaring lambdas, or LINQ, or any of the newer functional constructs.

Like I said, if you want more functional, there's F#, which is a dialect of ML.

I think your problem is just structural vs nominal typing, in that you can’t get away from the former.