Google Feedback on TypeScript 3.5

Post by dmix » Tue, Sep 10, 2019, 6:02 AM UTC

lonelappde wrote: post #125

dmix wrote: post #101

Earlier quoted context omitted.

All types are optional in typescript. I was just curious about Google's approach to it and if they had some standard practice of always copying the inferred type to get a great amount of coverage.

Copying the inferred type is the same as copying your runtime outputs into your tests. It's a statement that you believe the result is correct and it's on you to make that judgement call. It's not a policy to blindly copy everything, because that defeats the purpose of type checking and testing, turning your tests into " verify that nothing changed", not "verify that the system behaves as intended".

Post by rkangel » Tue, Sep 10, 2019, 8:06 AM UTC

papln wrote: post #111

rkangel wrote: post #34

Earlier quoted context omitted.

> Although it usually isn't necessary, it makes drastic improvements to the quality of error messages. It also provides valuable documentation. You can usually work out what a function does from just its type (and quite often, that's all you have to work with).

> just its type (and quite often, that's all you have to work with). which is a weakness in the culture of Haskell library authors and/or the ecosystem for contributing documentation patches.

Post by bsaul » Tue, Sep 10, 2019, 1:39 PM UTC

martinbooth wrote: post #144

bsaul wrote: post #53

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I'd love to have ML expressiveness. The only thing i'm a bit worried about is the I/O abstraction level. I'm not really looking for a GUI abstraction layer, but i'd like to be able to write to a file, or perform a network request, in a platform-independant way. I'm afraid this requires a little bit more than just a javascript transpiler target.

Reasonml is just an alternative syntax for ocaml so you can definitely use it for IO. It's bucklescript that is an alternative backend for the ocaml compiler which allows you to output js, but you don't need to use it

Post by fluffything » Wed, Sep 11, 2019, 10:46 AM UTC

squiggleblaz wrote: post #139

fluffything wrote: post #38

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IIRC there are a couple of Rust write ups about this. In Rust, inference is limited within functions. The language doesn't allow inferring the argument or return types of functions to avoid this kind of action at a distance. The function API is just one of the many arbitrary places where one can limit inference and require users to provide types. In other languages the module boundary might also be an appropriate pla…

The compiler should be capable of inferring the type as far as reasonably possible. But it should be an error to not specific the types of top level functions and class methods. This way, when you write const f = (a, b) => a + b the compiler can tell you to write: const f => (a: T, b: T): T => a + b or const f : (a: T, b: T) => T = (a, b) => a + b This would be effectively like GHC's typeholes, where the compiler wil…

    fn foo() { 42 } 

    fn foo() -> i32 { 42 } 

    fn bar(x: T, y: T) -> T { x + y }

    fn bar(x: T, y: T) -> T { x + y }

Post by wilgertvelinga » Mon, Sep 16, 2019, 9:09 AM UTC

bsaul wrote: post #109

wilgertvelinga wrote: post #72

Earlier quoted context omitted.

If you do go with TypeScript have a look at Nx. It's tooling around TypeScript monorepo that helps you do exactly what you want: write code once and share it between backend/multiple frontends. It suppports Express or NestJS in the backend and Angular, React, Web Components in the Frontend. https://nx.dev/ If you want to make it work with Ionic/NativeScript/Electron as well use xplat. https://github.com/nstudio/xplat

I don’t see anything regarding mobile platform (native).