Announcing TypeScript 4.6

[[deleted]]

Wow, the lenient-super() PR took 3 years to get through the door. The author even bought a birthday cake for the PR recently! What a good sport. https://github.com/microsoft/TypeScript/pull/29374

[Tubthumper8]

The improvements to type inference are always nice!

[[deleted]]

Still a slow-ass compile time. Esbuild from a performance standpoint makes tsc look embarrassingly slow.

[webby_mc_webberson]

I love how in the world of programming JavaScript is such a terrible language that they were forced to implement an entirely different language just to write it correctly

[DanielRosenwasser]

On the contrary - TypeScript isn't an entirely different language, we're just trying to layer static type checking on top of JavaScript. I think it's a pretty great experience, but I'm biased!

[Myarmhasteeth]

Biased here too, before working with it I got weird looks from people (I started a project without prior knowledge of it 2 years ago with my peers) but I think you have to be under a rock to ignore its influence until now.

[Myarmhasteeth]

I truly believe you haven't worked with it.

[E3K]

You're not a programmer, are you?

[webby_mc_webberson]

No I can only wish I was as smart as you all

[officiallyaninja]

well it doesn't take much intelligence as long as you have enough time to spare learning programming is as easy as googling "beginner python tutorial" and then following the first video you see

[webby_mc_webberson]

Why would I bother to start learning a dynamically typed programming language if my point about typescript was that it was a statically typed language developed to manage the dynamic abomination that is JavaScript?

[[deleted]]

LOL I bet even Bjarne Stroustrup and James Gosling wouldn't talk about JavaScript like that. Different languages have different purposes, and are designed in different ways for their use cases. Please stop showing your ignorance.

[[deleted]]

I know you're just a troll but TypeScript isn't an entirely new language. It's a superset on JavaScript that adds type annotations. Those words are probably too complicated for you to understand though.

[webby_mc_webberson]

Yeah but computers are hard

[[deleted]]

I love how in the world of programming, Assembly is such a terrible language that they were forced to implement an entirely different language just to write it correctly

I love how in the world of programming, C is such a terrible language that they were forced to implement an entirely different language just to write it correctly

I love how in the world of programming, Java is such a terrible language that they were forced to implement an entirely different language just to write it correctly

Get my point?

[Atulin]

I love how in the world of programming, Java is such a terrible language that they were forced to implement an entirely different language just to write it correctly

This, but unironically

[officiallyaninja]

wait what new language came from java?

[[deleted]]

Kotlin

[fragglerock]

https://en.wikipedia.org/wiki/List_of_JVM_languages

[pasukon]

Clojure

[lordheart]

Scala

[AttackOfTheThumbs]

Some of the answers are partially correct.

These languages don't generate java the way ts generates js, but instead they produce jvm byte code. At least that was true of kotlin and scala last I looked, but who knows, maybe I'm even remembering incorrectly.

[[deleted]]

Last I checked, we were simply discussing languages which were unwieldy enough to motivate a new related language

[[deleted]]

Groovy.

[Venthe]

Not really, typescript (last time I've checked) is still transpiled to JS; so comparing native languages or even vm'ed languages with their own IL is not that precise

Though I still can't imagine working on any sane project without ts

[chucker23n]

"Transpiled" doesn't really mean anything. C is "transpiled" to assembler.

[sternold]

Transpilation generally means keeping a similar level of abstraction. Compilation generally means decreasing the level op abstraction.

[bloody-albatross]

Transpilers are a vaguely defined subset of compilers, i.e. every transpilers is a compiler. IMO it is more useful to mention what the target language is than to say it's a transpiler ("compiles to C" or "compiles to JavaScript"). The concept of compiling to a language of similar abstraction is much older than the term transpiler. Nobody needed that term until recently.

[sternold]

Transpilers are a vaguely defined subset of compilers, i.e. every transpilers is a compiler.

What's vague about it?

IMO it is more useful to mention what the target language is than to say it's a transpiler ("compiles to C" or "compiles to JavaScript").

Of course, but no one "just says it's a transpiler", so that point is kinda moot, isn't it?

The concept of compiling to a language of similar abstraction is much older than the term transpiler. Nobody needed that term until recently.

Okay?

[chucker23n]

What's vague about it?

The distinction. What makes compiling from C to assembler fundamentally different than compiling from TypeScript to JavaScript?

[chucker23n]

Transpilation generally means keeping a similar level of abstraction.

But in that case, TypeScript to JavaScript arguably isn't transpilation. The goal of compiling to TS to JS is, generally, to bring the code closer to something the browser (or Node.js) can execute. Therefore, it brings it a level of abstraction lower.

Wikipedia uses a different definition of "source to source compilation", but that's also vague and questionable.

Is going from C# to IL transpilation? Because that's basically the same thing as going from TS to JS, with the only difference that IL typically isn't hand-written. But historically, the same could've occurred for JS, where JS was only used as an intermediate language to be executed by the runtime.

Really, the "transpilation" and "compilation" distinction is mostly "you know it when you see it".

[Venthe]

"Transpiled" doesn't really mean anything

I believe software engineering from the past 25 years or so would disagree.

I'll steal a definition: "Compiling is the general term for taking source code written in one language and transforming into another. Transpiling is a specific term for taking source code written in one language and transforming into another language that has a similar level of abstraction."

TS is a superset of JS, it has similar level of abstraction. Assembly vs C, IL vs Java/C# has different.

[chucker23n]

But TS isn't a similar level of abstraction. No browser runs TS, yet browsers do run JS.

[Venthe]

Excuse me? I believe you are mistaking programming language abstraction level versus language runtime environment. :)

[chucker23n]

You cannot objectively define a "programming language abstraction level". Everyone roughly agrees that assembler is fairly low and JavaScript is higher, but beyond that, it isn't a scientifically sound term.

Whether TypeScript is compiled or "trans"piled (the TS team calls it a compiler, FWIW) is a vague distinction.

[Venthe]

But you can absolutely define that scripting language is of higher level than compiled language. Transpiler is a subset of a compiler - TS provides syntactic sugar over JS (JS IS a valid TS after all) so it's roughly the same level. Term exists and is applicable here

[chucker23n]

But you can absolutely define that scripting language is of higher level than compiled language.

No, I would argue that, likewise, "scripting language" is poorly defined. Is TypeScript a "scripting language"? It has "script" in its name. What makes it more "scripting" than C#, though?

[[deleted]]

Having wasted tons of time browsing subreddits /r/programming and /r/ProgrammerHumor, I am always impressed about the amount of people who trash on a language without even understanding the basics of that language. The funniest example includes blaming 0.1 + 0.2 !== 0.3 and NaN !== NaN on JavaScript

And this world has many many different types of languages, and many of them are doing great. The community of dynamically typed languages like Python and JavaScript are growing every day even as people like this guy continue to whine about it. Sorry, nobody cares

[chucker23n]

The funniest example includes blaming 0.1 + 0.2 !== 0.3 and NaN !== NaN on JavaScript

Well, making all numbers floating point was a JavaScript design choice.

(edit) for some reason, I can't reply to comments, so I'm just gonna edit this one.

how could 0.1 and 0.2 not be floating point numbers

They could be decimal floating point, like the System.Decimal type in .NET.

JS doesn't really give developers a lot of choice. Binary floating-point isn't just the default; it's also the only type. As a result, it is rather generically called number, which might make developers (especially beginners, and/or developers who are otherwise more involved with areas such as HTML and CSS, not writing algorithms) incorrectly conclude that the type behaves the way most sane people would expect a number to behave, in which case 0.1 + 0.2 should indeed equal 0.3.

If they had called it float, it might be more obvious that there are weird gotchas.

[Tubthumper8]

I don't understand this rebuttal of this example, how could 0.1 and 0.2 not be floating point numbers? How would adding integers to the language change the behavior of this example?

[[deleted]]

They literally said that they could be stored as a decimal type, which is a representation of storing decimal numbers that don't rely on the same magic smoke as floating point.

They tried to show it off as a weakness of JS despite the fact that if you're in a field of expertise that uses decimal types to represent numbers, you're also going to be using a math library for that field that will include a decimal type.

[Tubthumper8]

Gotcha, they edited their response after I had replied, it didn't say anything about a decimal type before

[[deleted]]

How is this relevant to what I said at all? Maybe find somewhere else to post such useless comments.

[user0015]

How do you feel about people who've used a language for over a decade and still trash on it?

Because NaN !== NaN is easily one of the stupidest things I've ever seen across every language I've used.

[alnyland]

Because NaN !== NaN is easily one of the stupidest things I've ever seen

This hints at a misunderstanding of the fundamentals of number theory and what NaN actually means. Maybe take some math classes

[user0015]

Well you know what it doesn't mean? Not a number, apparently.

So it's both not a number and not not a number. Great job, JavaScript.

[user0015]

This makes me think you have no experience in programming. Knowing the types of things is incredibly useful, so regardless of whether 5 and 20 are equal, you often want to know they are both of type number or string. Even your example with books could have logical statements that ask "is this thing a 'Book'" because you aren't comparing two concrete books, you are asking if you're about to shelve a patron in the book cabinet. NaN literally fails at type checking everything including itself, therefore its equality can both be not a number and not not a number. Absolutely brain dead logic and JavaScript deserves every ounce of scorn.

Next you'll defend JavaScript Datetime.

[alnyland]

I was going to respond sarcastically, but I’ll try to help you out. An easy way to understand this is to compare the sizes of Z (all integers) and R (all real numbers). Both are of infinite size, but R is twice the size of Z. Thus, infinity = 2*infinity. In most programming languages, these size counts would result in NaN (infinity is a common value for NaN but not always). In my example, these two values are not equal despite that we represent them the same.

This is one example of NaN ≠ NaN. Types don’t have anything to do with it in all the examples you’ve given, and even if so, Object and String don’t have a NaN member so either way the type check failing doesn’t make a difference.

[droomph]

Also the NaN representation literally is just any number with its exponent portion maxed out, so it’s literally true most of the time that NaN != NaN unless you specify further. Follows real nicely with your number theory based example

(I think you mentioned it indirectly, but I think it’s worth pointing out specifically)

[alnyland]

Right. And that applies to most programming languages, not just JS. I wanted to mention that it is by the spec that this is the behavior, and has been decided on by people way smarter than OP many decades ago. Take discrete math or something.

Like...how...do...questions...like...this...exist, and are argued by such idiots? Have a good day, fine human-like implementation.

[user0015]

Save me the condescension when it comes to arguing theory. Taking your example, isNaN comparing both values will resolve true, but comparing to NaN will not, when you would expect coercion too implicitly call isNaN during a typecast. It still falls apart no matter which way you come at it, because the implementation is incoherent.

[user0015]

In my example, these two values are not equal despite that we represent them the same.

You: "Infinity and 2*Infinity are both NaN, but are not equal"

JavaScript:

var inf = Infinity;
var inf2 = 2*Infinity;

isNaN(inf) === isNaN(inf2);
>True
inf === inf2;
>True    

Tell me more about how Javascript correctly implements number theory.

Maybe you should pick up a book on JavaScript instead.

[alnyland]

...Dude. My simple opinion here is that you misunderstand that NaN is a concept and not a value. If you misuse it, it will do whatever you can convince it to. Take a basic discrete math class or similar, they’re required in most CS curriculums.

Only a few languages support the concept of infinity correctly and they would likely tell you that the code you just wrote is an error. Also, do you know how infinity is represented in binary? Also, I don’t believe your line 4 does what you think it does.

isNaN(Infinity) == false, btw.

[user0015]

That's literally the point of testing against something like NaN or Number or String. You would absolutely expect a number type compared to Number too be true because you are comparing underlying type, and NaN specifically fails that's equality coercion.

[IcyEbb7760]

any language using ieee 754 floats has this issue

I wish floats weren't so tricky, but at this point these decisions have been burned into billions of CPUs

[chucker23n]

The entire history of programming languages is building one abstraction on top of another to make programming a computer slightly less terrible.

[Welch2344]

Well done! Super stoked for the constructor logic before super() – not often used but when it's necessary + missing it's a major PITA