Ask HN: Will we see a TypeScript for Python? | Hacker News Reader

Ask HN: Will we see a TypeScript for Python?

11 pointsrrishi18 comments

Is there a need for such a thing like JS needed it? Is it viable?

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Python has an optional typing system which helps your IDE complete things and can be checked with tools like

https://mypy.readthedocs.io/en/stable/index.html

Plus there are compilers which can make faster code if you add static types

https://cython.readthedocs.io/en/latest/src/quickstart/cytho...

It's true that python has support for typing, and I do find that mypy helps produce better python code.

But I think a meaningful issue is that python's rich ecosystem of datascience and ML tooling often is at odds with meaningful type annotations. Roughly, you can end up with signatures that indicate that a value is a DataFrame or an ndarray or whatever, but there are a bunch of implicit assumptions on what columns are defined, or what how the shapes of two ndarrays line up, etc. It's easy for a codebase to end up paying the upfront cost of providing annotations, but without actually getting an improved ability to reason about or refactor code.

Python 3 has types and you can use Pydantic for validation.

https://docs.pydantic.dev

Not just Pydantic. Mypy is more commonly used and has something called mypyc that can compile your typed python code into C.

Isn't pydantic only for runtime validation?

In the abstract we have Psalm for PHP which I think is likely to eventually get rolled into PHP’s native type system. It’s so robust the major IDEs haven’t fully implemented it yet.

It doesn’t turn PHP into Haskell or anything but huge swaths of bugs are eliminated.

Python typing is optional and only checked statically, just like typescript typing. What else would a “Typescript for Python” add?

If you consider a language besides Python itself (which has optional typing), Nim could be an option, as the syntax is similar.

That's a completely different thing though. Python <> Nim is nothing like JS <> TS. And who cares about the syntax if you're using a completely different language, you can pick any typed language at that point.

As other mentioned, Python has already some tools around strong typing.

However they aren’t as extensive as TypeScript is to JavaScript. The community is also not much into types so you don’t have collections like Definitely Typed.

But the need exists and I guess it’s a matter of time until a tool becomes as popular and complete as typescript.

https://github.com/python/typeshed is Python's equivalent of DefinitelyTyped. I'm not 100% sure why it's not more of a popular thing the way DefinitelyTyped is; I think there might, to some extent, be different attitudes around the appropriateness of having third-party typings for packages, when the actual maintainer of the package isn't interested in providing first-party ones.

JS doesn't need TypeScript. When's the last time TS saved your JS project from disaster?

typescript isn't about saving a js project. its best when you get it at the beginning. where you can provide hints to your debugger and have type checkers that catch bugs proactively. you can just as easily any your way out of all the benefits.

Sorry if I'm being pedantic, was just responding to OP's phrasing of static typing being a "need" despite JS and Py having come so far without it. I'd say it's situational at best, and "you can turn it off" is probably TS's best feature.

If you're starting with TS, you can't really tell if it's useful or just a chore. I started a large Node project that a teammate moved to TS, saying the same thing about any that you did. I thought it'd be like Rust where it figures out the type for you, but no, any spreads. We replaced all those with explicit types, and I was writing fresh code in TS, but I realized it wasn't preventing any bugs that our integration tests wouldn't catch. It was just wasting my time with verbose types for things like SQL result rows that you could obviously tell were fine from the context. The other guy spent a ton of time fixing our build/deployment for TS, something that's taken lightly until you actually do it.

The project was pivoted for unrelated reasons, and I was left alone with it. I finally took it back to JS when I reached my last straw with TS, finding that it breaks the built-in Node profiler. Overall my velocity improved going back to JS. If TS were truly useful in that scenario, it'd be worth its weight for the reduced bugs that cost time to fix, but it wasn't.

pyright

Probably never. Modern Python is a joke, and so are attempts at to typify it like mypy.

I've built several multi-million dollar a year businesses using python.. It's hilarious.

And multi-million dollar businesses are built on Excel every day. Your point is what exactly?

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