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Hi, I'm on the Dart team, I'll try to answer the best I can. CoffeeScript doesn't really change the semantics of JavaScript at all, it mostly is just a new syn

Hi, I'm on the Dart team, I'll try to answer the best I can. CoffeeScript doesn't really change the semantics of JavaScript at all, it mostly is just a new syntax. I don't fine the syntax to be the worst thing about JavaScript, so CoffeeScript has never seems that compelling to me. TypeScript does a little more by offering types and classes, but it's still a superset of JavaScript and can't fix major issues because of backwards compatibility. I like TypeScript, but I prefer to go a lot farther. Dart fixes a lot of fundamental issues with JavaScript, largely related to having a well-defined structure that humans and tools can reason about. This makes it easier for the VM to optimize too. Here's a grab bag of things that Dart has over JavaScript: * Dart has libraries, and library scope, no global scope. All code must be imported to be used. * It has true classes with inheritance, interfaces and mixins. Objects are closed, so you can't accidentally add a new property because of a typo, and you get static warnings about undefined property names. * Dart has optional type annotations and a static type checker. We catch a lot of bugs when porting JavaScript code to Dart and adding types. * There are no top-level statements, only variable, function and class declarations. A program always starts at main(). * True lexical block scoping. No function scoping. * Final variables and library private names. * There are generics and they are reified. * 'this' is lexically bound, removing a whole swath of confusing patterns and bugs. * There is no implicit type coercion or boolean conversion. Being more explicit in boolean contexts reduces bugs. * There are real collections like Maps, Lists, and Sets. They are interfaces and can be implemented by users. * Dart has operator overloading * There is an actor-like unit of concurrency call Isolates * Metadata annotations (@something) can be processed by build-time and runtime tools. * noSuchMethod() let's you catch undefined method calls. All combined, I find Dart to be much easier to code in and much, much easier to read and navigate. Jump into a new Dart codebase and the types give you a lot of information. Even in code that's not typed, because it's statically analyzable you can jump to definitions and get documentation for fields and functions. At Google we see productivity is _much_ higher on Dart projects. Hope that helps a little!

rdtsc 12y ago
Hey great work, congratulations! I like the performance of Dart VM for server side. I remember it was so-so initially and then it got a huge performance boost. You could see a sharp jump on https://www.dartlang.org/performance/io/ https://www.dartlang.org/performance/io/ (now it almost disappeared to the left side due to the timeline moving)
- spankalee 12y ago
  Thanks! Well, thanks to the whole team, it's quite an effort. Server-side Dart is going to be a really great thing I think. It's by far my favorite server language already: much less verbose than Java, much more readable and maintainable than JavaScript, a similar "feel" to Python and Ruby in some ways, but with more structure and better performance. I'm excited about the future there.
- tveita 12y ago
  It's not obvious, but you can click and drag the chart to see older results. The drop in max latency is really notable. I assume that was caused by garbage collection improvements, but I can't find any details about what GC techniques the Dart VM currently implements.
phloxicon 12y ago
That's really helpful. Thanks. I have another question. C++ already has types, a main function, collections etc. and is really fast. What are the advantages of Dart over C++ with emscripten?
- spankalee 12y ago
  Dart is much more of a scripting language than C++. It makes as many code issues static warnings and runtime errors as it can, rather than runtime errors, so you can run a partially incorrect program. Dart is also strongly typed, doesn't have pointers, has GC, has no shared-memory concurrency, uses dynamic dispatch, don't require a compiler (for development), has full access the the DOM (with a much nicer API than in JavaScript!)...
  - k__ 12y ago
    Isn't the the API specified by the DOM? Like, when I use DOM in any language, it will be conform the the DOM spec, like having the same classes, methods, etc.?
    - tosh 12y ago
      Dart's DOM API is way nicer than the one from JavaScript since the Dart team had the ability to re-think naming & structure. This article has a nice summary of the improvements https://www.dartlang.org/articles/improving-the-dom/ https://www.dartlang.org/articles/improving-the-dom/
    - spankalee 12y ago
      Almost, but we have made it better. For instance, rather than use callbacks everywhere, most of our async APIs return Futures and Streams. All the "Array like objects", like NodeList, are actually lists in Dart. You can iterate over them and modify them list any other list. element.classses.add('foo') works, as well as some jQuery-isms like element.classes.toggle('foo', show). setInterval is replaced with the standard dart:async Timer class. There is a ton of cleanup in the dart:html library that makes programming the DOM nice. I'd say there will never need to be a jQuery equivalent in Dart.
skybrian 12y ago
I don't disagree but I'm wondering if a couple of these are ready to use yet: - Are metadata annotations really usable (at runtime)? If they're based on mirrors then it's my understanding they're to be avoided when using dart2js. - I haven't seen isolates used much. What's the status for them?
nailer 12y ago
Here's a list of Dart drawbacks. I like Dart's clean DOM API for the record, but here's what stops me using it: * Documentation aimed at Eclipse users who are familiar with Java and .net that like cutting edge web technologies, rather than existing web developers. * No npm, and little documentation emphasis on running on servers * Poor integration with massive amount of existing JS technologies * Surprising amount of redundant tokens for a language released in 2011. Semicolons, really? * Most importantly: it's been nearly three years and Dart has made little to no impact on the world of frontend development. Even non-production Dart use is unheard of on frontend circles, and has less users than coffeescript or Typescript.
- discreteevent 12y ago
  * Documentation aimed at Eclipse users who are familiar with Java and .net that like cutting edge web technologies, rather than existing web developers. Eclipse users? How could you tell that the documentation is aimed at Eclipse users? What is it about documentation that could make it Eclipse user biased? * No npm, and little documentation emphasis on running on servers Dart is a different language to javascript so its got it's own package manager called pub. If you google "dart package manager" you will find it straight away. If you look at any dart documentation or examples you will see references to it. Did you expect that if you change your programming language you would have the same package manager? No other programming language has npm either. * Poor integration with massive amount of existing JS technologies I think it's pretty good but they are working to improve it. See https://news.ycombinator.com/item?id=7972907 https://news.ycombinator.com/item?id=7972907 * Surprising amount of redundant tokens for a language released in 2011. Semicolons, really? A surprising amount sounds like there are very many indeed. Apart from delimiters like semicolons and braces (which have advantages in a modern language and are used by many) can you list some of the other redundant tokens? Dart seems very terse to me. * Most importantly: it's been three years and Dart has made little to no impact on the world of frontend development. Even non-production Dart use is unheard of on frontend circles, and has less users than coffeescript or Typescript. Remember that Dart was opened up long before it was recommended as being stable. Even at that, can you name one other language where the user had some choice (unlike, say, js) that had widespread adoption in a 3 year timeframe?
optymizer 12y ago
Hi! What is the current state of browser adoption for Dart? Wikipedia seems very pessimistic about it [1]. [1] http://en.wikipedia.org/wiki/Dart_(programming_language)#Browser_adoption http://en.wikipedia.org/wiki/Dart_(programming_language)#Bro...

rdtsc 12y ago

Hey great work, congratulations! I like the performance of Dart VM for server side. I remember it was so-so initially and then it got a huge performance boost. You could see a sharp jump on https://www.dartlang.org/performance/io/ https://www.dartlang.org/performance/io/ (now it almost disappeared to the left side due to the timeline moving)

spankalee 12y ago
Thanks! Well, thanks to the whole team, it's quite an effort. Server-side Dart is going to be a really great thing I think. It's by far my favorite server language already: much less verbose than Java, much more readable and maintainable than JavaScript, a similar "feel" to Python and Ruby in some ways, but with more structure and better performance. I'm excited about the future there.
tveita 12y ago
It's not obvious, but you can click and drag the chart to see older results. The drop in max latency is really notable. I assume that was caused by garbage collection improvements, but I can't find any details about what GC techniques the Dart VM currently implements.

phloxicon 12y ago

That's really helpful. Thanks. I have another question. C++ already has types, a main function, collections etc. and is really fast. What are the advantages of Dart over C++ with emscripten?

spankalee 12y ago
Dart is much more of a scripting language than C++. It makes as many code issues static warnings and runtime errors as it can, rather than runtime errors, so you can run a partially incorrect program. Dart is also strongly typed, doesn't have pointers, has GC, has no shared-memory concurrency, uses dynamic dispatch, don't require a compiler (for development), has full access the the DOM (with a much nicer API than in JavaScript!)...
- k__ 12y ago
  Isn't the the API specified by the DOM? Like, when I use DOM in any language, it will be conform the the DOM spec, like having the same classes, methods, etc.?
  - tosh 12y ago
    Dart's DOM API is way nicer than the one from JavaScript since the Dart team had the ability to re-think naming & structure. This article has a nice summary of the improvements https://www.dartlang.org/articles/improving-the-dom/ https://www.dartlang.org/articles/improving-the-dom/
  - spankalee 12y ago
    Almost, but we have made it better. For instance, rather than use callbacks everywhere, most of our async APIs return Futures and Streams. All the "Array like objects", like NodeList, are actually lists in Dart. You can iterate over them and modify them list any other list. element.classses.add('foo') works, as well as some jQuery-isms like element.classes.toggle('foo', show). setInterval is replaced with the standard dart:async Timer class. There is a ton of cleanup in the dart:html library that makes programming the DOM nice. I'd say there will never need to be a jQuery equivalent in Dart.

skybrian 12y ago

I don't disagree but I'm wondering if a couple of these are ready to use yet: - Are metadata annotations really usable (at runtime)? If they're based on mirrors then it's my understanding they're to be avoided when using dart2js. - I haven't seen isolates used much. What's the status for them?

nailer 12y ago

Here's a list of Dart drawbacks. I like Dart's clean DOM API for the record, but here's what stops me using it: * Documentation aimed at Eclipse users who are familiar with Java and .net that like cutting edge web technologies, rather than existing web developers. * No npm, and little documentation emphasis on running on servers * Poor integration with massive amount of existing JS technologies * Surprising amount of redundant tokens for a language released in 2011. Semicolons, really? * Most importantly: it's been nearly three years and Dart has made little to no impact on the world of frontend development. Even non-production Dart use is unheard of on frontend circles, and has less users than coffeescript or Typescript.

discreteevent 12y ago
* Documentation aimed at Eclipse users who are familiar with Java and .net that like cutting edge web technologies, rather than existing web developers. Eclipse users? How could you tell that the documentation is aimed at Eclipse users? What is it about documentation that could make it Eclipse user biased? * No npm, and little documentation emphasis on running on servers Dart is a different language to javascript so its got it's own package manager called pub. If you google "dart package manager" you will find it straight away. If you look at any dart documentation or examples you will see references to it. Did you expect that if you change your programming language you would have the same package manager? No other programming language has npm either. * Poor integration with massive amount of existing JS technologies I think it's pretty good but they are working to improve it. See https://news.ycombinator.com/item?id=7972907 https://news.ycombinator.com/item?id=7972907 * Surprising amount of redundant tokens for a language released in 2011. Semicolons, really? A surprising amount sounds like there are very many indeed. Apart from delimiters like semicolons and braces (which have advantages in a modern language and are used by many) can you list some of the other redundant tokens? Dart seems very terse to me. * Most importantly: it's been three years and Dart has made little to no impact on the world of frontend development. Even non-production Dart use is unheard of on frontend circles, and has less users than coffeescript or Typescript. Remember that Dart was opened up long before it was recommended as being stable. Even at that, can you name one other language where the user had some choice (unlike, say, js) that had widespread adoption in a 3 year timeframe?

optymizer 12y ago

Hi! What is the current state of browser adoption for Dart? Wikipedia seems very pessimistic about it [1]. [1] http://en.wikipedia.org/wiki/Dart_(programming_language)#Browser_adoption http://en.wikipedia.org/wiki/Dart_(programming_language)#Bro...