Node.js adds experimental support for TypeScript

Post by cstrahan » Thu, Jul 25, 2024, 2:51 PM UTC

epolanski wrote: post #275

mananaysiempre wrote: post #260

Earlier quoted context omitted.

> A minifier can't guarantee that such expressions won't be used, so it cannot optimize property accesses. Given TypeScript’s type system is unsound, neither could it even if it tried, right? I guess Flow could, but well, here we are.

What do you mean by unsound exactly. I'm asking because there's no accepted definition of what an unsound type system is. What I often see is that the word unsound is used to mean that a type system can accept types different to what has been declared, and in that case there's nothing unsound about ts since it won't allow you to do so.

  function messUpTheArray(arr: Array): void {
      arr.push(3);
  }
  
  const strings: Array = ['foo', 'bar'];
  messUpTheArray(strings);
  
  const s: string = strings[2];
  console.log(s.toLowerCase())
  

Post by tpm » Thu, Jul 25, 2024, 2:59 PM UTC

VMG wrote: post #313

tpm wrote: post #291

Earlier quoted context omitted.

Java has type inference. Also if a type alias is just a new name for a existing type, then you can always do something like class MyNewClass extends OldClass {}; (of course it's not just a new name, it's also a new class, but it's also still a OldClass, and you are out of luck if OldClass is final or sealed) Java also has interfaces, of course. And optional properties (using Optional) and strict null checks, when you…

> type inference very limited, for instance you must declare the type of a public method > alias as you point out it's not > Java also has interfaces, of course but you have to implement them explicitly > strict null checks, when you want that, you can use it if we start accepting static analysis tools then C has null checks as well I guess

Post by ahuth » Thu, Jul 25, 2024, 3:00 PM UTC

hajile wrote: post #317

winter_blue wrote: post #35

Earlier quoted context omitted.

Flow (by Facebook) used to be fairly significant in the JavaScript several years ago, but right now it's somewhat clear that TypeScript has won rather handily.

Flow tries to be sound and that makes it infinitely better than TS where the creators openly threw the idea of soundness out the window from the very beginning.

Post by ahuth » Thu, Jul 25, 2024, 3:01 PM UTC

hajile wrote: post #322

BiteCode_dev wrote: post #212

Eventually, node might allow JS to introspect those types. That would be a huge win. Right now in Python, great tools like pydantic exist because Python can introspect said types, and generate checks out of them. This mean you can define simple types, and get: - type checking - run time data check - api generation - api document generation Out of a single, standard notation. Right now in JS, things like zod have to d…

If JS ever adds type checking, I hope it doesn't choose Typescript. We need a type system that is actually sound and TS is intentionally unsound. We need a type system that doesn't allow bad coding practices like TS does. We need a type system that enforces program design that allows programs to be fast. We need a Hindley Milner type system. If you want a module to be typed, add a `"use type"`. This should disallow b…

Post by tracker1 » Thu, Jul 25, 2024, 3:06 PM UTC

murmansk wrote: post #185

dobladov wrote: post #180

Earlier quoted context omitted.

You can have this now adding types with JSDoc and validating them with typescript without compiling, you get faster builds and code that works everywhere without magic or need to strip anything else than comments. The biggest pain point of using JSDoc at least for me was the import syntax, this has changed since Typescript 5.5, and it's now not an issue anymore.

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