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Announcing TypeScript 2.1

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Re: Announcing TypeScript 2.1

#81

Post by pimterry »

euroclydon wrote: post #30

One thing I never understood with Babel is which features are shimmed in the output JS and which features are re-implemented? What I means is: I didn't know how to tell Babel which browsers I was targeting, and I'm pretty sure that some of their feature implementations do not feature test the platform before activating, since they were so compiled in. Is that the case? Also, do you have to tell TypeScript your target…

You do tell TypeScript which runtime you're targeting, and that's how it decides how to compile it. You either set `target` in your tsconfig.json, or you provide `--target` on the command line.

Docs: https://www.typescriptlang.org/docs/handbook/compiler-option...

Re: Announcing TypeScript 2.1

#82

Post by johnfn »

ggregoire wrote: post #40
timruffles wrote: post #11

If you still haven't given TypeScript a go as a Javascripter, now is a great time to do so. Whether you end up adopting it or not, it's interesting to get the types out of your mind and into the code. The first time you feel the speed/confidence of refactoring with accurate 'Find usages', you'll decide if the undeniable overhead of types is worth it.

> The first time you feel the speed/confidence of refactoring with accurate 'Find usages', you'll decide if the undeniable overhead of types is worth it. For your information: in VSCode, the "Find all references" and "Rename symbol" work out-of-the-box, even if your code isn't typed. Edit and disclaimer: Not sure why I'm getting downvoted, my comment doesn't contradict parent message. I personally type my code too (w…

> For your information: in VSCode, the "Find all references" and "Rename symbol" work out-of-the-box, even if your code isn't typed.

I didn't downvote, but this seems incorrect to me. I'm sure that it works in small code bases, but once your code gets large enough (and dynamic enough) it's going to have to start missing things.

Re: Announcing TypeScript 2.1

#83

Post by jtmarmon »

Can someone comment on the difference in reliability between using typescript and a natively statically typed language like haskell or scala? Is there any? Or is the type safety really as good when you use ts

Re: Announcing TypeScript 2.1

#84

Post by ng12 »

Longwelwind wrote: post #39
zdragnar wrote: post #8

It's interesting to me that all of the initial reactions I've seen to this announcement have been around the introduction of async and object spread, which are available with babel, but the typescript specific features such as mapped types are completely ignored. I don't really have any particular meaning behind that observation, only that it tickled my funny bone a little bit.

Maybe it is me, but I feel like mapped types and keyof are terrible features, and using them would be a sign of a bad design/architecture. In general, I don't think using a string that represents a static symbol (such as the name of a var, an attribute or a class) is a good idea. I try to keep a simple stack (Typescript + NPM at the moment), and I prefer to wait for Typescript to have the feature I want, than to inst…

Simple example: keyof allows you to safely describe objects which only partially fit an interface.

  interface Values {
    foo: string,
    // etc...
  }

  let keys: keyOf Values

  function initialize(defaults: {[key: keys]: string}) {...}
Now the defaults object can only contain valid keys from Values.

Re: Announcing TypeScript 2.1

#85

Post by RyanCavanaugh »

g00gler wrote: post #23
timruffles wrote: post #11

If you still haven't given TypeScript a go as a Javascripter, now is a great time to do so. Whether you end up adopting it or not, it's interesting to get the types out of your mind and into the code. The first time you feel the speed/confidence of refactoring with accurate 'Find usages', you'll decide if the undeniable overhead of types is worth it.

I have to second Mr.timruffles. After using TS in a couple of projects I grew to miss it when I couldn't use it. If you don't like the C#-ness of Typescript, try using Facebook's flow. Typing isn't a magic bullet, typescript isn't even type safe, but it sure makes development easier and your apps more stable.

Where do you perceive the C#-ness of TS coming from? TS and Flow are ~90% identical (most programs accepted by one would be accepted by the other) and TS adds only a few purely optional syntactic features (namespace, enum) that are widely found in other languages.

Re: Announcing TypeScript 2.1

#86

Post by pimterry »

k__ wrote: post #66

Are there any plans to catch something like this: function f(x: any): T { return x }

That would defeat the point of 'any', right? It's for variables that you want to allow to do anything (including be a T) without the compiler complaining.

If you don't want that behaviour, don't given x 'any' type. In that case there I'd probably use '{}' instead, and then use type guards (https://www.typescriptlang.org/docs/handbook/advanced-types.... to convince TypeScript that it's a T (whatever that means).

Re: Announcing TypeScript 2.1

#87

Post by whatever_dude »

Noseshine wrote: post #72

Question: Is it possible to have a setup with TypeScript where it is guaranteed that no code changes occur other than removal of the type information? I started using Flow, found what it can and can't do and would like to try TypeScript. But only if I can have "types-only", I don't want my code "translated" in any way. I'm writing for the latest node.js version and not for x different browsers, I want to use exactly…

> Is it possible to have a setup with TypeScript where it is guaranteed that no code changes occur other than removal of the type information?

Yes and no.

Typescript does a little bit of filling in the gaps of some missing features if the target platform does not support a feature you used. So your compiled code will still be ES6 (or ES5), but it may have some boilerplate added to polyfill for something if ES6 or ES5 (or others..) do not officially support it.

Re: Announcing TypeScript 2.1

#88

Post by johnfn »

ryanSrich wrote: post #68
timruffles wrote: post #11

If you still haven't given TypeScript a go as a Javascripter, now is a great time to do so. Whether you end up adopting it or not, it's interesting to get the types out of your mind and into the code. The first time you feel the speed/confidence of refactoring with accurate 'Find usages', you'll decide if the undeniable overhead of types is worth it.

Can anyone weigh in on TypeScript vs Elm?

Elm is really cool language that's pushing a lot of boundaries. Use it for learning or for small projects.

TypeScript is a highly practical and pragmatic language. Use it for anything serious.

Re: Announcing TypeScript 2.1

#89

Post by stcredzero »

klodolph wrote: post #60
Longwelwind wrote: post #39

Earlier quoted context omitted.

Maybe it is me, but I feel like mapped types and keyof are terrible features, and using them would be a sign of a bad design/architecture. In general, I don't think using a string that represents a static symbol (such as the name of a var, an attribute or a class) is a good idea. I try to keep a simple stack (Typescript + NPM at the moment), and I prefer to wait for Typescript to have the feature I want, than to inst…

I think there are two main kinds of developers who use TypeScript. Some developers come from traditional statically-typed languages, like C#/Java/C++/etc, and expect the language to conform to their idea of "good design". For these developers, "mapped types" are "not good design". Other developers come from JavaScript, Python, Ruby, or other duck-typed languages and think, "I know that this object is just a dictionar…

I'm sure you've heard the arguments by dynamic language lovers who talk about how restrictive/slow/painful it is to write in a static type system, and I'm sure you're as tired of that argument as I am.

At this point in time, it's a bit of a false dichotomy. It just amounts to a programming tool based on a form of meta-data. Of course people are going to have different ideas about the cost-benefit of that tooling. Of course, people are going to have differing opinions on how much of that tooling is worthwhile. Most of the problems with online discussions about this kind of tooling, come from people forgetting that it's just a discussion about tooling.

Re: Announcing TypeScript 2.1

#90

Post by ausjke »

ygra wrote: post #41
ausjke wrote: post #38

Been a Linux developer for ages C# was never my taste, I'm still a bit Microsoft-hatred as of now(Visual Studio Code is the only item I adopted for JS development, the rest languages I still use vi/Geany). How tightly TS is related to C#? That has been the main reason I had not tried TS seriously so far. Don't want to have anything to do with C#. I know...

They are not related at all, except in who is their original designer. However, if you are really so fundamentally opposed to anything and everything a certain language represents then you've got to hate a lot of languages for a really, really petty reason.

For the record I embrace all new stuff except for two, that is Microsoft at-large and systemd.
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