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This is basically where I am at. Most libraries and applications are trivially typed even in languages with relatively poor type systems like Go and Java. The n

This is basically where I am at. Most libraries and applications are trivially typed even in languages with relatively poor type systems like Go and Java. The necessity, or even benefit, of weak and/or dynamic typing is extremely rare and most languages have workarounds or escape hatches for those exceedingly rare cases. Dynamic typing also makes a ton of optimizations basically impossible and even after monumental efforts languages like Javascript are still quite slow, inconsistent and memory inefficient outside of trivial benchmarks.

diggan 3y ago
> Javascript are still quite slow, inconsistent and memory inefficient outside of trivial benchmarks. I thought this meme was dead already. Of course, you might not be able to squeeze out the same amount of performance compared to a brilliantly written C or Rust program, but for what it is, JavaScript is pretty damn fast already. DOM manipulation on the other hand, is still a very common bottleneck people come across when writing typical JavaScript code.
- fsdjkflsjfsoij 3y ago
  > but for what it is, JavaScript is pretty damn fast already. It's fast compared to other dynamically typed language implementations but it's still very slow compared to basically all of the popular statically typed languages.
  - wilde 3y ago
    JustJS would like a word https://www.techempower.com/benchmarks/#section=data-r20&test=composite https://www.techempower.com/benchmarks/#section=data-r20&tes...
    - fsdjkflsjfsoij 3y ago
      Trivial benchmarks where all of the significant data structures and networking are done in C++ and the tiny amount of Javascript is just passing some strings around. I guess it's "fast" if you can restrict yourself to little more than hello world where you do nothing more than pass a few strings to functions written in faster languages. Notice that in the Java, C#, Go, Rust, Swift or Ocaml benchmarks almost all of the underlying data structures and much of the networking stack are built in the respective language. This is not possible with Javascript, Python, Ruby etc. because it would be ludicrously slow and extremely memory inefficient.
  - cogman10 3y ago
    > It's fast compared to other dynamically typed language implementations true > it's still very slow compared to basically all of the popular statically typed languages. Not true. The main slowdown for javascript (AFAIK) is the checks the optimizer has to put into place to ensure the assumptions it's made about the type are still valid. If, however, those assumptions are valid then javascript ends up emitting pretty much the same assembly that you'd see for and highly optimized statically typed language. In fact, there are some circumstances where it can beat a language like C++ or Rust due to the fact that it has to incorporate runtime information into optimizations. With C++ or rust, if you add dynamic dispatch, unless you are doing PGO and whole program optimization, you are pretty much sunk with 2 memory lookups on every function call. This is the case where javascript can end up beating C++/Rust. (All of this is talking about hot code after warmup. During the initial execution javascript will almost certainly always be slower). Part of the proof of this was asm.js, the precursor to wasm. V8 at the time it was introduced could execute asm.js nearly as fast as what firefox could do with it's optimized asm.js compiler. That is, when you stripe out all the actions that make javascript slow, it very often ends up being just as fast as a compiled language. What stuff ends up making it slow? Generally speaking, stuff that makes the types unpredictable (adding fields, removing fields, sending in a number and a string and expecting the VM to be able to handle both). You can see a lot of this writeup around the discussions about why Dart was originally "optionally typed". Basically, the entire selling point to make dart fast was simply to remove the abilities to dynamically change types like you have in javascript. With that, the VM authors at the time were capable of making a VM that's every bit as fast as what Java has.
    - gpderetta 3y ago
      > With C++ or rust, if you add dynamic dispatch, unless you are doing PGO and whole program optimization, you are pretty much sunk with 2 memory lookups on every function call. This is the case where javascript can end up beating C++/Rust. GCC at least is capable of speculative devirtualization by using local heuristics, without PGO. And of course it is capable of devirtualizing in many cases when the knowledge actual type can be constant-propagated. Also note that the vast majority of calls are not dynamic in C++ (as opposed to most dynamic languages), so devirtualization is significantly less impactful.
  - PH95VuimJjqBqy 3y ago
    I think what cracks me up about this conversation is that it's an almost verbatim repeat of a conversation I had on reddit a few weeks ago. There's a certain segment of the developer population that I don't think realizes just how fast C and C++ are. Javascript is _relatively_ fast when compared to other dynamic languages, but not when compared to C, C++, FORTRAN, etc.
da4c30ff 3y ago
The take I have is that with a dynamically typed language you still have a static analysis step. It’s just that the analysis happens in your and other developers’ brain and it is objectively worse. I honestly can’t think of a single thing in favor of dynamic typing. I write Clojure in my day job and it’s insane how often we have issues where it would have been immediately caught by a static type check.
- waffletower 3y ago
  May I interest you in some unmentioned static analyzer possibilities for Clojure: https://github.com/clj-kondo/clj-kondo https://github.com/clj-kondo/clj-kondo https://github.com/jonase/eastwood https://github.com/jonase/eastwood You seem dissatisfied with Clojure in your day job -- I am sure that there are others that would be happier in your situation.
  - da4c30ff 3y ago
    I'm aware of these, but thank you nevertheless. Clojure has plenty of nice things balancing the scales, so it's not all pain and misery!
- stefcoetzee 3y ago
  I'd love to learn more. Are you part of a large team (enterprise or SMB, whatever you can share)? How have you experienced using Type Clojure, spec, Malli, etc. to determine correctness? I've only worked on solo projects with Clojure, with most of it fitting into my head. I imagine with teams of size N > 1 things can change quite a bit.
vasergen 3y ago
> Javascript are still quite slow Can you describe your usecase for which JavaScript is slow? There are many languages that are slower than js like python or elixir, but they are doing just fine, that's why I won't agree that js is slow, but sure there are cases for which js just wasn't designed, and any CPU intensive task will be slow, but there are ways to get around it as well.
throw10920 3y ago
> Dynamic typing also makes a ton of optimizations basically impossible and even after monumental efforts languages like Javascript are still quite slow, inconsistent and memory inefficient outside of trivial benchmarks. Please provide evidence for this extreme claim. I can point to benchmarks[1] where JavaScript is competitive with or even better than compiled static-typed languages like Java. (any argument that those are "trivial benchmarks" is automatically invalid without actual empirical evidence) [1] https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/javascript.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/...

diggan 3y ago

> Javascript are still quite slow, inconsistent and memory inefficient outside of trivial benchmarks. I thought this meme was dead already. Of course, you might not be able to squeeze out the same amount of performance compared to a brilliantly written C or Rust program, but for what it is, JavaScript is pretty damn fast already. DOM manipulation on the other hand, is still a very common bottleneck people come across when writing typical JavaScript code.

fsdjkflsjfsoij 3y ago
> but for what it is, JavaScript is pretty damn fast already. It's fast compared to other dynamically typed language implementations but it's still very slow compared to basically all of the popular statically typed languages.
- wilde 3y ago
  JustJS would like a word https://www.techempower.com/benchmarks/#section=data-r20&test=composite https://www.techempower.com/benchmarks/#section=data-r20&tes...
  - fsdjkflsjfsoij 3y ago
    Trivial benchmarks where all of the significant data structures and networking are done in C++ and the tiny amount of Javascript is just passing some strings around. I guess it's "fast" if you can restrict yourself to little more than hello world where you do nothing more than pass a few strings to functions written in faster languages. Notice that in the Java, C#, Go, Rust, Swift or Ocaml benchmarks almost all of the underlying data structures and much of the networking stack are built in the respective language. This is not possible with Javascript, Python, Ruby etc. because it would be ludicrously slow and extremely memory inefficient.
- cogman10 3y ago
  > It's fast compared to other dynamically typed language implementations true > it's still very slow compared to basically all of the popular statically typed languages. Not true. The main slowdown for javascript (AFAIK) is the checks the optimizer has to put into place to ensure the assumptions it's made about the type are still valid. If, however, those assumptions are valid then javascript ends up emitting pretty much the same assembly that you'd see for and highly optimized statically typed language. In fact, there are some circumstances where it can beat a language like C++ or Rust due to the fact that it has to incorporate runtime information into optimizations. With C++ or rust, if you add dynamic dispatch, unless you are doing PGO and whole program optimization, you are pretty much sunk with 2 memory lookups on every function call. This is the case where javascript can end up beating C++/Rust. (All of this is talking about hot code after warmup. During the initial execution javascript will almost certainly always be slower). Part of the proof of this was asm.js, the precursor to wasm. V8 at the time it was introduced could execute asm.js nearly as fast as what firefox could do with it's optimized asm.js compiler. That is, when you stripe out all the actions that make javascript slow, it very often ends up being just as fast as a compiled language. What stuff ends up making it slow? Generally speaking, stuff that makes the types unpredictable (adding fields, removing fields, sending in a number and a string and expecting the VM to be able to handle both). You can see a lot of this writeup around the discussions about why Dart was originally "optionally typed". Basically, the entire selling point to make dart fast was simply to remove the abilities to dynamically change types like you have in javascript. With that, the VM authors at the time were capable of making a VM that's every bit as fast as what Java has.
  - gpderetta 3y ago
    > With C++ or rust, if you add dynamic dispatch, unless you are doing PGO and whole program optimization, you are pretty much sunk with 2 memory lookups on every function call. This is the case where javascript can end up beating C++/Rust. GCC at least is capable of speculative devirtualization by using local heuristics, without PGO. And of course it is capable of devirtualizing in many cases when the knowledge actual type can be constant-propagated. Also note that the vast majority of calls are not dynamic in C++ (as opposed to most dynamic languages), so devirtualization is significantly less impactful.
- PH95VuimJjqBqy 3y ago
  I think what cracks me up about this conversation is that it's an almost verbatim repeat of a conversation I had on reddit a few weeks ago. There's a certain segment of the developer population that I don't think realizes just how fast C and C++ are. Javascript is _relatively_ fast when compared to other dynamic languages, but not when compared to C, C++, FORTRAN, etc.

da4c30ff 3y ago

The take I have is that with a dynamically typed language you still have a static analysis step. It’s just that the analysis happens in your and other developers’ brain and it is objectively worse. I honestly can’t think of a single thing in favor of dynamic typing. I write Clojure in my day job and it’s insane how often we have issues where it would have been immediately caught by a static type check.

waffletower 3y ago
May I interest you in some unmentioned static analyzer possibilities for Clojure: https://github.com/clj-kondo/clj-kondo https://github.com/clj-kondo/clj-kondo https://github.com/jonase/eastwood https://github.com/jonase/eastwood You seem dissatisfied with Clojure in your day job -- I am sure that there are others that would be happier in your situation.
- da4c30ff 3y ago
  I'm aware of these, but thank you nevertheless. Clojure has plenty of nice things balancing the scales, so it's not all pain and misery!
stefcoetzee 3y ago
I'd love to learn more. Are you part of a large team (enterprise or SMB, whatever you can share)? How have you experienced using Type Clojure, spec, Malli, etc. to determine correctness? I've only worked on solo projects with Clojure, with most of it fitting into my head. I imagine with teams of size N > 1 things can change quite a bit.

vasergen 3y ago

> Javascript are still quite slow Can you describe your usecase for which JavaScript is slow? There are many languages that are slower than js like python or elixir, but they are doing just fine, that's why I won't agree that js is slow, but sure there are cases for which js just wasn't designed, and any CPU intensive task will be slow, but there are ways to get around it as well.

throw10920 3y ago

> Dynamic typing also makes a ton of optimizations basically impossible and even after monumental efforts languages like Javascript are still quite slow, inconsistent and memory inefficient outside of trivial benchmarks. Please provide evidence for this extreme claim. I can point to benchmarks[1] where JavaScript is competitive with or even better than compiled static-typed languages like Java. (any argument that those are "trivial benchmarks" is automatically invalid without actual empirical evidence) [1] https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/javascript.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/...