I don't understand why anyone would use Node.js

Your first point seems to indicate you are, in fact, trolling:

> Javascript is not fundamentally easier to code in than Java.

You provide nothing to support this assertion which wildly contradicts the accepted conventional wisdom[1,2].

1. http://www.htmlgoodies.com/beyond/javascript/article.php/347...

"JavaScript contains a much smaller and simpler set of commands than does Java. It is easier for the average weekend warrior to understand. ... JavaScript's main benefit is that it can be understood by the common human. ... JavaScript is a little more forgiving than Java. It allows more freedom in the creation of objects. Java is very rigid and requires all items to be denoted and spelled out."

2. http://sislands.com/coin70/week1/javajs.htm

"Java, due to its complex syntax, rules, and restrictions, may seem daunting for those without programming experience. JavaScript, on the other hand, is easy to use and learn. You can create sophisticated applications just by just learning some commands, syntax rules, and the object model of the browser."

Aside from that, if you truly don't understand why anyone would choose node.js, that sounds like a failure of imagination.

I think you take the wrong tack on a badly formulated sentence. Consider, the rest of the "Ask HN"-article compares with Ruby and discusses mostly the effect of trading development speed for execution speed.

So do you have references about the development speed of Javascript [edit: for competent programmers]? As compared to Java and the usual scripting languages like Ruby, Perl etc.

(I am asking; I don't really know. [Edit: To be really really clear -- I ask because I am surprised by the claim. Javascript seems like a simplified scripting language.])

An 'average weekend warrior' or people 'without programming experience' who are daunted by the complexity of Java should not be implementing server applications (see PSN security issues). They are complicated independent of the language, and anyone capable of implementing one will not be tripped up by syntax.

The authors points were all legitimate, there was no trolling there. I think a lot of us have quietly wondered why there was a need for a Javascript based server framework; maybe a lot of the hype was driven by frustrated/advanced front-end developers that wanted to work w/ familiar tools combined with the new/shiny factor. It doesn't seem exceptional in any respect outside of being implemented in JS right now.

That said, you should be happy for this kind of post. It means that node.js is catching on enough that it's getting critical attention. Same thing happened to Rails, and to Java before that.

"An 'average weekend warrior' or people 'without programming experience' who are daunted by the complexity of Java should not be implementing server applications (see PSN security issues)"

Disagree. If well-trained professional programmers were the only people implementing server applications, we wouldn't be where we are today. The fact that people can tinker, teach themselves, put together a highly-insecure server just to share their implementation with others provides a huge benefit to all programmers and the industry in general. Thus trolling.

And again, "I don't understand why anyone would use node.js" is link bait trolling. Anyone means anyone. I bet if the OP really thought long and hard (or just for 10 seconds) he/she could come up with at least a reason one person would use node.js. Coming up with one person makes the OP's title a false statement.

You are coming up with a blanket judgement based on a small subset of a post (and in my opinion, not interpreting it as the poster intended). It read to me like he was talking about production usage, not tinkering. Node.js is slower and more resource intensive than Erlang (if you're comparing just async/message passing models), less productive for _most_ programmers than RoR or PHP, not as battle tested (security/stability) as Java, and fewer 3rd party libraries than most.

I don't even know about the state of development tools like debuggers and profilers. My understanding is that Node.js still has stability issues (memory leaks or GC bugs?) and doesn't utilize multi-core machines very well, either.

I'm all for tinkering, and I expect Node.js to be very successful and as an additional benefit to improve the V8 engine. But you're being overly sensitive to call this mild critique (albeit with a bad title) trolling.

Yeah, I agree that I got a bit worked up in my response and my language was a bit stronger than it needed to be. I guess it was driven a bit by:

a) nodejs is resulting in a ton of interesting projects. whether it is the best design decision to use nodejs in these projects instead of something else is another question. the creativity nodejs has helped spark is awesome in itself.

b) if the OP was referring to creating battle-tested server applications, he/she should have made that clearer. yes nodejs is immature and crashes left and right.

c) OP titles like this one (i.e. generalized statement the OP knows to not be true) do not foster productive discourse and community

1. I think you're wrong. I would agree that JavaScript's syntax is not great, but it's still better than Java's. (And dynamic typing, whatever your complaints with it, does significantly reduce how verbose the language is.) Also, first-class functions are a huge benefit for me.

Also a lot of JS's syntactical issues/verbosity can be alleviated with libraries like Underscore. Start using CoffeeScript and you're miles ahead of Java in terms of syntax and verbosity, and you make some of JS's more annoying issues a lot easier to avoid.

2. Yes, you do care about performance, to a certain point. If everything I was doing had to immediately be available at Google scale, then yes, I'd consider Java a lot more seriously. However, most of the stuff I do doesn't have to scale to millions of simultaneous connections on just a handful of servers. Absolute performance is not my highest consideration, and NodeJS absolutely is more productive for me than Java.

I think you're missing a couple of very important points, which are why I think NodeJS is the best tool for some tasks.

First, and by far most importantly, it has Socket.IO, which is by far the best choice library when you're doing anything in real time. It is fantastic, and is a huge part of the reason why I use NodeJS for certain classes of applications.

Second, there is value to being able to share code between the server and the client for nontrivial web applications. Most code doesn't get shared, but not having to have separately maintained models for the server and client is really helpful.

For me, the 'cool factor' doesn't come into it at all. I enjoy programming in JS and even moreso in CoffeeScript. I dislike programming in Java. And when I'm not doing something that has to be hugely scalable, Java's only real advantage is raw speed, and NodeJS has vastly superior tools for doing what I'm trying to do (real-time webapps), NodeJS is the clear choice.

Off topic: "Java's only real advantage is raw speed...". Tell this to some one 10yrs back and they would laugh. Java has come a long way.

I think, using node.js or a Java stack is just a matter of personal choice.

I think the main strength is the fact that you are writing JavaScript both on the client side and the server side. You don't have to mentally switch languages or anything. Even though people don't think that it has an effect, it does. And while, even in JS, you'll write things slightly differently when doing client/server side work but it still would take less brain power than changing client/server paradigms as well as changing languages.

I'm the author of the CoffeeScript book from PragProg, which includes a chapter on Node.js.

I've done a fair amount of server-side development in Java and Ruby. What I like most about Node.js is the feeling that you can be as close to the metal as you like. You don't have the endless boilerplate of every Java web framework, or the extensive "magic" of RoR. With Node and a framework like Express, you can understand things at the level of "let me look at this HTTP request and decide how to respond to it." This, to me, is beautiful:

    app = require('express').createServer()

    app.get '/', (req, res) ->
      res.send 'hello world'

    app.listen 3000

It's going to take more time to build a full-featured web app that way than with RoR or Django, but you'll understand it better and it'll scale well. For something that's only been around for two years, Node.js has a remarkable ecosystem—you can tell that a lot of very smart people are gravitating to it.

And yes, being able to use the same language for both your client-side and server-side code is pretty dang cool. It's also practical. Historically, development teams have tended to focus on the server-side and learn JS only well enough to hack together some jQuery into doing what they need on the front-end. The result has been a lot of buggy and lackluster front-end code. Node.js gives teams a compelling reason to master JavaScript, and to learn tools like CoffeeScript. And that's great news for the web as a whole.

'With Node and a framework like Express, you can understand things at the level of "let me look at this HTTP request and decide how to respond to it."'

Sure, but roughly the same kind of thing is available in most other serverside languages. Python has Flask, Ruby has Sinatra, and PHP also has several mini-frameworks.

Right, I like Sinatra a lot. But there's substantially more magic there than in Express, which is actually a pretty thin (yet powerful) wrapper around Node's low-level HTTP API.

There's a lot to like about node.js - I'm playing with node+express+coffeescript right now, and it's fun.

That said, some things I don't like so much:

- "inception" style development. Callbacks within callbacks, especially if you are doing db queries for example. Gets cumbersome and annoying very quickly.

- lack of ecosystem. Though improving, nowhere near Ruby, PHP or Python (or Java/JVM for that matter).

- lack of use cases. Hard to say where it would be a valid replacement for existing webapps. Chatbots and games, sure, but most client work I do is boring old CRUD. Rails and Django provided huge productivity gains here, nodejs, not so much.

- hype. I get the feeling a lot of this is driven by front end developers who suddenly feel they've been given the keys to the server-side kingdom without having to learn another language. Much of what node.js offers exists elsewhere and better, for example Haskell or Erlang (though not as accessible to mere mortals, perhaps).

> 1 - Javascript is not fundamentally easier to code in than Java.

What makes you think this? I think the idea that Javascript is a better language than Java is a big part of what draws people to things like Node.js.

His point makes even less sense when you consider CoffeeScript

+1 because once you remove all the embarrassingly bad syntax from javascript, and use only the good parts, the way coffeescript does, then you have one of the best languages on the market (minus step debugging and tooling support... but those are coming soon).

No, but it's fundamentally a lot more fun to program in than Java.

Seriously. I've been spending the week writing views and lists for CouchDB. Working in CoffeeScript (for the syntax) and using JS patterns has made me the happiest camper.

One caveat before commenting is that I haven't written a major app in Node.js and I use Python most of the time (vs. Java).

I don't think the decision to use Node.js should be based on the fact it uses Javascript. Currently, Javascript has a much more interesting ecosystem than it has at any other time. Just as Rails took many collective practices and managed to communicate them clearly to a huge group of developers, I think a similar trend is happening in Javascript. From this perspective, Node.js is appealing because it rides atop this Javascript revolution with tools like Coffeescript, Backbone, etc.

Outside of the language decision, I think people are choosing to use Node.js b/c of its programming model. There are many applications that are relatively easy to code for when you can assume a constant connection between two processes. Where Node.js seems to excel is in these service level, socket based servers that may or may not have a web component. Likewise, Node.js also aims to be very nix friendly in that it tries to use simple processes for scaling instead of relying on more complicated application / language specific tools. This adherence to nix patterns is also very advantageous to some people.

Finally, as people start finding use cases where async really is a good idea, Node.js ends up being a decent option. Having done some async programming in Python, it is very difficult because the async assumption needs to be made throughout in order to avoid blocking. My impression is that the experience in other languages is similar, where no library is truly able to make the async paradigm seamless. Node.js has been written from scratch to support this model and many developers understand it via their Javascript experience. It therefore can be a good option when compared to including something like Stackless, EventMachine, etc. in their applications.

I think the key point here is that Node.js has managed to hit something of a sweet spot in that it is async, uses a language that is having something of a renaissance and uses *nix to make its integration obvious.

Again, I don't use Node.js very heavily at all, but that is my impression as to why people would choose it over other technologies.

"The reports of having 100k connections is great but again, any server in C or Java written correctly should be able to do the same thing..."

Only a few people can write them correctly besides, they're not fun to hack with. Feels like work.

I just finished coding a web service in both Java, PHP, and node.js. Java took 1848 lines of code. PHP 548. Node 201. In my tests Node uses much less CPU and has way better performance than Java or PHP. 201 lines is far easier to get working than 1848.

I have no love for callback-based programming, but assuming you want to do it (node.js), you really need closures, which Java does not have.

> 1 - Javascript is not fundamentally easier to code in than Java. I wouldn't make that statement with Ruby for example, but I've done lots of all 3.

A lot of people coming from front-end development on the web prefer JavaScript over Java.

Personally, to me (and probably a lot of people who are actually working on serious projects on node) - node fits beautifully in certain contexts. For e.g. socket based streaming is ridiculously easy using socket.io.

Callback based programming is not fun - but once you get used to the syntax, it's not unbearable either.

Well this is not an answer any single person can or should want to give you, but I'll try to summarize the big picture anyway:

1. Nodejs is really well documented code. This is very rare, and much more so in the Javascript world.

2. It has a nice, easy to use package manager. In comparison, I have a hard time containing my boiling rage over Maven...

3. Nodejs was marketed as very fast. Although async+fast solutions exist with other languages and frameworks too, they require you to be very knowledgable in those areas. Nodejs is a no-brainer. They practically guaranteed you that you are not going to get bad performance, because in Javascript you can't use blocking calls. Nodejs users care about performance. Java programmers tell you to not worry about it. (attention: gross generalization)

4. Javascript programmers don't know about better solutions. In fact, I'd say that most of the PHP crowd doesn't know better solutions either. There's your huge market.

5. Javascript is easy to program in. You can have your production server up and running with a few lines of code. I believe an experienced Java programmer when he says that the LOC (lines of code) are not much more with Java. But you do need to learn a lot more to get to that point. Nodejs is self-contained.

Personally, I do not want to program large projects in a dynamic language. I still made a small prototype in Nodejs before moving on though. It's too messy for me :)

The important part in Node.js is not "js" it's "node". The design pattern encouraged is a network of micro-utilities nodes.

Ryan Dahl (node.js creator) did not choose javascript because it was cool but because the language was the most suited to its needs. In fact we started several project based on the same principles in different languages (C, lua, and others). Javascript is a good fit because it has no previous history on how to do I/O (which is the main focus in node.js design) except AJAX. It sure has been very helpful in making it popular. But the point is that there could have been Node.whatever. [1]

Now if you choose to use Node.js because it's cool, that's fine, but you're missing the important points :

1 - It is easy to write. Yes it is. Not only because it's javascript (or coffeescript) but also because the API is very well designed. Because of the agreed on convention of coding, it's also very easy to use modules even when these are not as much documented as node itself. It also would not be as easy to write if it were C or Java. In this netty example [2] you need 4 different classes to write an echo client/server which sums up to approx. 120 lines of code without comments and imports. The node version is 15 lines long at best [3] and clearer.

2 - It is efficient. Sure, in raw calculation, lots of other languages are faster. What makes node efficient is asynchronous I/O. You can do async I/O in any other programming language. It's just not that easy and most importantly you don't have to if you are lazy. The fastest language to write async I/O in is probably C. And you can do just that using libuv, the C library behind node.js which is incredibly faster without the Javascript layer.

3 - It works at the session/presentation level. Of course it's not as convenient as writing your php file, but it's necessary to ensure that the async model is respected (which is what makes it efficient, which is the reason why you came here in the first place). If you want cool javascript to replace php/JEEE/asp, you can use Jaxer.

Of course there are other important points that I'm missing here both because they don't come to mind at the moment and because you should experiment by yourself.

[1] http://www.youtube.com/watch?v=L_JKb61EalQ [2] http://docs.jboss.org/netty/3.2/xref/org/jboss/netty/example... [3] http://nodejs.org/

> 1 - Javascript is not fundamentally easier to code in than Java. I wouldn't make that statement with Ruby for example, but I've done lots of all 3.

It depends on what you are writing. But personally, I find that languages with first class functions are much more powerful than languages without. Closures fall out of this as well. So on that point, JavaScript stomps all over Java.

From the anecdotal evidence of all the infrastructure the Node community has created, I'd say the FFI must be substantially better as well. I've coded in JNI and it was not fun. There's a lot of good code already out there that doesn't run inside a JVM, and to many, it's pretty important to be able to access that.

Node isn't entirely javascript. The http parser, for example, is a very fast implementation in C.

The javascript part is taking advantage of a big race between several major vendors to make a really fast javascript implementation.

In tests of massively concurrent loads, node.js is very fast and reliable. (That's not to say it's the only good solution.)

The libraries are entirely asynchronous. They put an emphasis on making it easy for an average programmer to get things right, instead of running into hidden pitfalls.

(I haven't used it in anger yet, but I hung around on the mailing list for a good while.)

1) What language is easier to code in is really determined by the proficiency in various languages of the developer.

2) Performance is not all that matters. Getting back to the easier to code argument, productivity is equally as important. If the developers of the product are more proficient in Javascript, then working around the performance issues is likely cheaper than waiting for the developers to learn another language better, or to hire developers who know Java or C or whatever and understand the vision of the product being created.

Not to mention these days performance is cheap. Run several instances of node.js behind some sort of load balancer/proxy on a multi-core server and you're good to go. Heck, my little cheap Rackspace cloud server has 4 cores available to it.

The language and platform is only part of the equation to developing a product. Whatever allows you to create a product you can develop quickly and maintain in the future is the right choice.

Disclaimer: I tried node.js, decided it wasn't for me and went back to Tornado (python). I however can understand why someone more proficient in javascript would choose node.js. It was really easy to set up and get into writing code with.

"productivity is equally as important"

Node has a lot of good features, but programmer productivity isn't one of them currently. There are close to zero full-featured frameworks with "the works" (Geddy comes close, but is no longer maintained, and Express is essentially no more than a mini-framework). You simply have to write a lot of code yourself to do stuff that in other frameworks such as Django is included by default. Add to that the fact that deploying a Node site isn't nearly as easy and fast as deploying a PHP site, and you've got a setup that isn't ideal in terms of productivity.

though not a great justification, and I'm hoping hackers far better than myself can defend nodejs (if only for my entertainment/interest). But using node is actually VERY fun, I cant quantify it but I find it a lot more enjoyable than any of the other server side languages I know.

and using it in conjunction with coffeescript only increases the pleasure of working with it. I can only but dream of the day that coffeescript needn't be compiled into JavaScript first.

I, too, do not understand why anybody would use Node.js... when you have Erlang :)

And since you speak of Java, I also do not understand why anybody would use that either. If you have a thing for the JVM, at least do yourself a favor and use a decent language, like Scala.

Erlang's syntax is terrifying to users only experienced with more mainstream languages, and hard to work with for users not specifically experienced with it. LFE or Reia may solve some of those problems, though I don't have experience with them.

Erlang syntax is just that, a (quirky, different, non-mainstream) syntax. Takes about 2 weeks to get used to, and it's simpler than, say, C syntax. The core concepts, such as functional programming and the Actor model will be harder to grok for an imperative-bred programmer, but I think it's totally worth it, at least for the perspective that it will give you.

Speaking of Reia, its author just announced he's stopping development on it. There's another, similar project called Elixir that is considered to be Reia's spiritual successor.

Having moved on from Java to JavaScript on the server, I strongly disagree with the first point. I've had the pleasure of rewriting a webapp I had previously written in Java in JavaScript and found the latter to be much more compact and easier to maintain, largely due to JavaScript's dynamic nature.

My only gripe with Node is the obsession with the asynchronous programming style and overly eager use of callbacks. However, there are workarounds, such as my Common Node library (http://olegp.github.com/common-node/).

Ymmv - personally I think JavaScript is a lot easier than Java, but Ruby might actually be harder than Java as the Ruby docs are very messy. I still prefer Ruby to Java, though.

I used Python as a scripting engine and it is fabulous. I see a similar role for node.js.

I use node because it's fun.

You can't program the client in Java.

And how is that relevant? I've heard the argument "Your backend developers can work on the front end too" -- but its a tired argument. Any developer who can't already do both has no place working for a company producing web-based software.

For example, you don't have to write validating logic for inputs twice.

That somebody can do both things should, in my opinion not mean that he has do both things.

You can use the same code at the front end and at the back end.

There's a huge army of teams who aren't competent to do both, judging by the number of sites that fail completely if the client isn't trusting and running javascript. Node.js seems like a good solution for unobtrusive enhancement, making reliable semantic resources that may still optimize out many server round trips with mobile code.

Ideally, would you write your web application using one language, or ten?

And that is how it's relevant. Any developer who can't grasp this concept has no place working for a company producing web-based software.

I would choose to write it in however many languages fit the various pieces best. To choose otherwise would be ill-advised.

By "however many languages fit the various pieces best," did you mean the most or the fewest?

I mean I wouldn't make technical decisions dogmatically.

I think everyone here will back you up on that, but don't infer that zinxq is advocating choice by technical dogma. I read their post as simply asking for an explanation for node.js's accelerating popularity; of course there are many factors, but its ability to reduce lexical context switching is obviously a major component. To argue otherwise would be ill-advised.

In a perfect world you would be correct. But answer me this:

How many Java backend engineers know how to unit test javascript, how to make modular templates (e.g. writing their own tags, or nesting/tiling their JSP's), how to systematically minify their code in production and use CDN's ... or even how to use any design patterns in Javascript?

Sure you can! http://code.google.com/webtoolkit/

(But who wants to is a separate question.)

I stand corrected.