Michigan TypeScript
2 HN recommenders · recommended in 4 months, 2025
1:01:31 · 102K views · Mar 11, 2025
An interview with Anders Hejlsberg, lead architect of TypeScript, about porting the TypeScript compiler to Go. He covers the 10x type-checking speedup, lower memory use, and why Go was chosen.
HN points to it as the authoritative answer to why the team picked Go rather than C# or Rust, citing timestamps on cyclic data structures and garbage collection.
9 comments from Hacker News
Anders Hejlsberg explains here: this video . TL;DW: - C# is bytecode-first, Go targets native code. While C# does have AOT capabilities nowadays this is not as mature as Go's and not all platforms support it. Go also has somewhat better control over data layout. They wanted to get as low-level as possible while still having garbage collection. - This is meant to be something of a 1:1 port rather than a rewrite, and the old code uses plain functions and data structures without an OOP style. This suits Go well while a C# port would have required more restructuring.
If you are wondering why not Rust instead of Go, they outline why Rust was not chosen. This is a port not a reimplementation. Many of the data structures can not easily be ported to Rust, such as Nodes with cyclic dependencies. Check the longer interview here: this video Also, I think the discussion on esbuild's choice of language applies here as well as it has a large similarity. You can find it here on hn
While I'm most familiar with C#, and haven't used Ruby professionally for almost a decade now, I think we'd be better off looking at typescript, for at least 3 reasons, probably more. 1. Flowsensitivity: It's a sure thing that in a dynamic language people use coding conventions that fit naturally to the runtime-checked nature of those types. That makes flow-sensitive typing really important. 2. Duck typing: dynamic languages and certainly ruby codebases I knew often use ducktyping. That works really well in something like typescript, including really simple features such as type-intersections and unions, but those features aren't present in C#. 3. Proof by survival: typescript is empirically a huge success. They're doing something right when it comes to retrospectively bolting on static types in a dynamic language. Almost certainly there are more things than I can think of off the top of my head. Even though I prefer C# to typescript or ruby _personally_ for most tasks, I don't think it's perfect, nor is it likely a good crib-sheet for historically dynamic languages looking to add a bit of static typing - at least, IMHO. Bit of a tangent, but there was a talk by anders hejlsberg as to why they're porting the TS compiler to Go (and implicitly not C#) - this video - I think it's worth recognizing the kind of stuff that goes into these choices that's inevitably not obvious at first glance. It's not about the "best" lanugage in a vacuum, it's a about the best tool for _your_ job and
this video [19:14] why not C#? Dimitri: Was C# considered? Anders: It was, but I will say that I think Go definitely is -- it's, I'd say, the lowest-level language we can get to and still have automatic garbage collection. It's the most native-first language we can get to and still have automatic GC. In C#, it's sort of bytecode first, if you will; there is some ahead-of-time compilation available, but it's not on all platforms and it doesn't have a decade or more of hardening. It was not geared that way to begin with. Additionally, I think Go has a little more expressiveness when it comes to data structure layout, inline structs, and so forth. For us, one additional thing is that our JavaScript codebase is written in a highly functional style -- we use very few classes; in fact, the core compiler doesn't use classes at all -- and that is actually a characteristic of Go as well. Go is based on functions and data structures, whereas C# is heavily OOP-oriented, and we would have had to switch to an OOP paradigm to move to C#. That transition would have involved more friction than switching to Go. Ultimately, that was the path of least resistance for us. Dimitri: Great -- I mean, I have questions about that. I've struggled in the past a lot with Go in functional programming, but I'm glad to hear you say that those aren't struggles for you. That was one of my questions. Anders: When I say functional programming here, I mean sort of functional in the plain sense that we're dealing wi
Anders answers that question here - this video Transcript: "But I will say that I think Go definitely is much more low-level. I'd say it's the lowest level language we can get to and still have automatic garbage collection. It's the most native-first language we can get to and still have automatic GC. In contrast, C# is sort of bytecode-first, if you will. There are some ahead-of-time compilation options available, but they're not on all platforms and don't really have a decade or more of hardening. They weren't engineered that way to begin with. I think Go also has a little more expressiveness when it comes to data structure layout, inline structs, and so forth."