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I'm not saying I never ever run into bugs due to dynamic types such as method/variable typos, I just think it's much more rare than people make it out to be. If

I'm not saying I never ever run into bugs due to dynamic types such as method/variable typos, I just think it's much more rare than people make it out to be. If that sort of thing happens a lot in a project you basically have very little tests. I'm confident in saying it happens to me maybe once in a few months - and that's working in a super dynamic environment of Rails. The Null error does happen, but that happens in java as well.

dkempner 7y ago
But how often do you forget what properties are required for the config object that is the third argument to your function?
- joelbluminator 7y ago
  I'm not saying it never happens, I just really need to think hard on when it last happened. You're talking about a method that requires a certain param but doesn't raise an exception if you leave it out and then behaves in a buggy way. Again, not something happening a lot.
  - com2kid 7y ago
    Everytime I construct that object I'd have to look up what the fields are, either docs (lol yeah right) or by looking at previous calls. Bonus if my previous usage was incorrect and I didn't notice and I end up copying that same mistake again and again! TypeScript saves me probably 15+ minutes a day of just switching back and forth looking up what parameters are needed. It is a one time tax to make everything I do more pleasant.
- joelbluminator 7y ago
  btw can't you potentially write methods that receive arbitrary number of arguments in java as well? https://docs.oracle.com/javase/1.5.0/docs/guide/language/varargs.html https://docs.oracle.com/javase/1.5.0/docs/guide/language/var...
  - monkpit 7y ago
    You’re referring to a variadic function, which can be written in most modern languages. The commenter you are replying to is talking about a function of fixed-arity, with a config object with required props. Which props are required? A Typed language will tell you immediately “for free”.
glued 7y ago
Tests are only as good as the person who writes them. Typescript is just another way to build confidence in your codebase. I have found it to be an invaluable tool in large projects especially on teams with various levels of experience.
- joelbluminator 7y ago
  Well code in general is only as good as the person who writes it. You can write static code that compiles and doesn't work at all, you still need to test it. Only in static languages testing it become way more complicated.
  - monkpit 7y ago
    What are the types of tests you’d need to write in a statically-typed language that are more complicated than their dynamically-typed counterparts?
jeswin 7y ago
A big benefit with static typing is the ability to refactor easily. It takes time to get design and code right, in a way that captures the requirements well as well as code quality. With static typing, you get immediate feedback while you tune your code. Most of the popular large JS projects have switched (or are switching) to TypeScript (or Flow for React, though they'd have used TypeScript today). So that supports the argument in favor of TypeScript.
- joelbluminator 7y ago
  I don't know the js world that well, can you provide links that show most js developers use typescript? There are arguments for both. There are still millions of python/php/js/ruby devs and codebases that use dynamic code. It could be that in javascript the gains of types are more felt than in Ruby/Python. '' + [] will raise an error in Ruby and probably python too.
  - angus_gh 7y ago
    > can you provide links that show most js developers use typescript? They didn't say most developers had switched, they said most large projects have switched
com2kid 7y ago
Not having to go to the code and investigate what the types of am object's fields are. That alone can make TS worth it. Heck just getting auto-complete on an object's members.
- hombre_fatal 7y ago
  Also any sort of combinator usage or functional programming reminds me of why static typing is so useful. A few layers of higher order functions / combinators and I don't remember if I have `value` or a `{ value: value }` container (like map vs flatMap). Or which stage of the curry I'm at. Oh right, I'm at foo(a, _, c) but thought I was at foo(a, b, _). If you can't even remember the last time you've encountered a runtime error, you are by my definition writing trivial code or not writing much code at all.
- vorpalhex 7y ago
  If you need autocomplete for your object, that's a sign your objects are probably a bit too big.
- SketchySeaBeast 7y ago
  Yes. I'm part of a long term support team - teams do their work and transition it to me. I support a lot of solutions at once, none of which I've built or been able to spend a significant time getting into the guts of. Having the code do a lot of the investigation for me is incredibly valuable. It helps me quickly build a mental model of the small slice of the code I'm dealing with.
winter_blue 7y ago
Tests are a very poor and verbose duct-tapey replacement for succinct and powerful static type information. Static types massively make it easier to understand new code. I can actually see the structure of the data that's getting passed around, with types.
- joelbluminator 7y ago
  Huh? tests are there to make sure your code behaves correctly, e.g it works. Don't you do that in static land?
  - winter_blue 7y ago
    You write tests for things that actually matter ... like you know, testing functionality. You don't waste time writing tests that simply check if all the arguments received the right type. This is taken care of by the type checker. Besides, the biggest benefit of types is readability.
    - joelbluminator 7y ago
      I don't see tests as you describe in dynamic languages much. E.G this is how you would test Rails controllers https://gitlab.com/gitlab-org/gitlab/-/blob/master/spec/controllers/search_controller_spec.rb https://gitlab.com/gitlab-org/gitlab/-/blob/master/spec/cont... . I don't think its that different than java world.
cageface 7y ago
About 1/3 of the bugs on my current project would have been prevented just by strict null checking alone. I've seen bugs on projects with 100% test coverage that would have been caught by types. Dynamic typing was a mistake.
- joelbluminator 7y ago
  Are you talking about using Optional or things like that in java? That's pretty recent so you can't say that's a property of a static language. And it brings its own problems with it.
  - cageface 7y ago
    What problems does it bring with it? It's just a tool that automatically tells you where you need to deal with possible null values. It's far easier than trying to catch every possible place this can happen with loads and loads of manually written tests. Not all static languages give you this but the trend is pretty clear with Typescript, Swift, Kotlin etc.
    - joelbluminator 7y ago
      I can't say the use case for Optional is even well defined https://stackoverflow.com/questions/26327957/should-java-8-getters-return-optional-type/26328555#26328555 https://stackoverflow.com/questions/26327957/should-java-8-g... . I'm no good in java, this is just what I find on the web.
      - cageface 7y ago
        Have you actually worked in a language with good, first-class null handling? I'm not surprised that something tacked onto java very recently is awkward to use but in Swift or Typescript it's much easier than wrapping if foo.nil? calls everywhere and much more effective.
      - xzel 7y ago
        What? The use case for an optional type has been been documented for decades and iirc is sourced from type theory. See it’s usage in Haskell (Maybe type) as one aged example. Also, that stack over flow is pretty well clear on what it should be used for imo.
jamil7 7y ago
I don't write much JS/TS anymore but I had a weird relationship with Typescript. I work daily with Swift and sometimes Kotlin and found myself slightly disappointed about the kinds of things that Typescript would let me do, I'm not sure if this is up to the underlying limitations of compiling to JS or that the settings of the project I was on wasn't configured properly. It adds quite a bit of overhead as a dependency when you have to bring in typings and keep these updated then make everything work with tests and storybook etc. It's a huge improvement over Javascript though and it's likely unfair to compare it to those other languages.
- valuearb 7y ago
  I think the future is a strongly typed language like Kotlin/Swift to webassembly on front end, and compiled to Bytecode on back end.

dkempner 7y ago

But how often do you forget what properties are required for the config object that is the third argument to your function?

joelbluminator 7y ago
I'm not saying it never happens, I just really need to think hard on when it last happened. You're talking about a method that requires a certain param but doesn't raise an exception if you leave it out and then behaves in a buggy way. Again, not something happening a lot.
- com2kid 7y ago
  Everytime I construct that object I'd have to look up what the fields are, either docs (lol yeah right) or by looking at previous calls. Bonus if my previous usage was incorrect and I didn't notice and I end up copying that same mistake again and again! TypeScript saves me probably 15+ minutes a day of just switching back and forth looking up what parameters are needed. It is a one time tax to make everything I do more pleasant.
joelbluminator 7y ago
btw can't you potentially write methods that receive arbitrary number of arguments in java as well? https://docs.oracle.com/javase/1.5.0/docs/guide/language/varargs.html https://docs.oracle.com/javase/1.5.0/docs/guide/language/var...
- monkpit 7y ago
  You’re referring to a variadic function, which can be written in most modern languages. The commenter you are replying to is talking about a function of fixed-arity, with a config object with required props. Which props are required? A Typed language will tell you immediately “for free”.

glued 7y ago

Tests are only as good as the person who writes them. Typescript is just another way to build confidence in your codebase. I have found it to be an invaluable tool in large projects especially on teams with various levels of experience.

joelbluminator 7y ago
Well code in general is only as good as the person who writes it. You can write static code that compiles and doesn't work at all, you still need to test it. Only in static languages testing it become way more complicated.
- monkpit 7y ago
  What are the types of tests you’d need to write in a statically-typed language that are more complicated than their dynamically-typed counterparts?

jeswin 7y ago

A big benefit with static typing is the ability to refactor easily. It takes time to get design and code right, in a way that captures the requirements well as well as code quality. With static typing, you get immediate feedback while you tune your code. Most of the popular large JS projects have switched (or are switching) to TypeScript (or Flow for React, though they'd have used TypeScript today). So that supports the argument in favor of TypeScript.

joelbluminator 7y ago
I don't know the js world that well, can you provide links that show most js developers use typescript? There are arguments for both. There are still millions of python/php/js/ruby devs and codebases that use dynamic code. It could be that in javascript the gains of types are more felt than in Ruby/Python. '' + [] will raise an error in Ruby and probably python too.
- angus_gh 7y ago
  > can you provide links that show most js developers use typescript? They didn't say most developers had switched, they said most large projects have switched

com2kid 7y ago

Not having to go to the code and investigate what the types of am object's fields are. That alone can make TS worth it. Heck just getting auto-complete on an object's members.

hombre_fatal 7y ago
Also any sort of combinator usage or functional programming reminds me of why static typing is so useful. A few layers of higher order functions / combinators and I don't remember if I have `value` or a `{ value: value }` container (like map vs flatMap). Or which stage of the curry I'm at. Oh right, I'm at foo(a, _, c) but thought I was at foo(a, b, _). If you can't even remember the last time you've encountered a runtime error, you are by my definition writing trivial code or not writing much code at all.
vorpalhex 7y ago
If you need autocomplete for your object, that's a sign your objects are probably a bit too big.
SketchySeaBeast 7y ago
Yes. I'm part of a long term support team - teams do their work and transition it to me. I support a lot of solutions at once, none of which I've built or been able to spend a significant time getting into the guts of. Having the code do a lot of the investigation for me is incredibly valuable. It helps me quickly build a mental model of the small slice of the code I'm dealing with.

winter_blue 7y ago

Tests are a very poor and verbose duct-tapey replacement for succinct and powerful static type information. Static types massively make it easier to understand new code. I can actually see the structure of the data that's getting passed around, with types.

joelbluminator 7y ago
Huh? tests are there to make sure your code behaves correctly, e.g it works. Don't you do that in static land?
- winter_blue 7y ago
  You write tests for things that actually matter ... like you know, testing functionality. You don't waste time writing tests that simply check if all the arguments received the right type. This is taken care of by the type checker. Besides, the biggest benefit of types is readability.
  - joelbluminator 7y ago
    I don't see tests as you describe in dynamic languages much. E.G this is how you would test Rails controllers https://gitlab.com/gitlab-org/gitlab/-/blob/master/spec/controllers/search_controller_spec.rb https://gitlab.com/gitlab-org/gitlab/-/blob/master/spec/cont... . I don't think its that different than java world.

cageface 7y ago

About 1/3 of the bugs on my current project would have been prevented just by strict null checking alone. I've seen bugs on projects with 100% test coverage that would have been caught by types. Dynamic typing was a mistake.

joelbluminator 7y ago
Are you talking about using Optional or things like that in java? That's pretty recent so you can't say that's a property of a static language. And it brings its own problems with it.
- cageface 7y ago
  What problems does it bring with it? It's just a tool that automatically tells you where you need to deal with possible null values. It's far easier than trying to catch every possible place this can happen with loads and loads of manually written tests. Not all static languages give you this but the trend is pretty clear with Typescript, Swift, Kotlin etc.
  - joelbluminator 7y ago
    I can't say the use case for Optional is even well defined https://stackoverflow.com/questions/26327957/should-java-8-getters-return-optional-type/26328555#26328555 https://stackoverflow.com/questions/26327957/should-java-8-g... . I'm no good in java, this is just what I find on the web.
    - cageface 7y ago
      Have you actually worked in a language with good, first-class null handling? I'm not surprised that something tacked onto java very recently is awkward to use but in Swift or Typescript it's much easier than wrapping if foo.nil? calls everywhere and much more effective.
    - xzel 7y ago
      What? The use case for an optional type has been been documented for decades and iirc is sourced from type theory. See it’s usage in Haskell (Maybe type) as one aged example. Also, that stack over flow is pretty well clear on what it should be used for imo.

jamil7 7y ago

I don't write much JS/TS anymore but I had a weird relationship with Typescript. I work daily with Swift and sometimes Kotlin and found myself slightly disappointed about the kinds of things that Typescript would let me do, I'm not sure if this is up to the underlying limitations of compiling to JS or that the settings of the project I was on wasn't configured properly. It adds quite a bit of overhead as a dependency when you have to bring in typings and keep these updated then make everything work with tests and storybook etc. It's a huge improvement over Javascript though and it's likely unfair to compare it to those other languages.

valuearb 7y ago
I think the future is a strongly typed language like Kotlin/Swift to webassembly on front end, and compiled to Bytecode on back end.