The comparison is not entirely correct. The difference between node.js and express.js in the level of abstraction:

1. Node.js is a *run-time environment* for building server-side *event-driven i/o application* using javascript.
2. Express.js is a *framework based on node.js* for building *web-application* using principles and approaches of node.js

So, if you write web-application, you can try to use Express.js. In all other cases, it does not suit for you.

Express is built on top of Node, so yes Express adds more features. Node is just a Javascript environment with libraries to make it easy to write software, where Express extends Node specifically to make webservers easy to write.

Express/Connect adds the concept of middleware, a simplified way of managing different routes, automated integration with several templating engines and a bunch more.

Express js is built on top of the Node.js framework. 

Express js uses node.js itself and provides more features to build applications on top Node.js 

http://expressjs.com/, if you look at this link itself it says **Express - node.js web application framework.** 

I would like to understand how to use [dis (the dissembler of Python bytecode)](http://docs.python.org/library/dis.html). Specifically, how should one interpret the output of [`dis.dis`](http://docs.python.org/library/dis.html#dis.dis) (or [`dis.disassemble`](http://docs.python.org/library/dis.html#dis.disassemble))?

.

*Here is a very specific example (in Python 2.7.3):*

&lt;!-- language: lang-py --&gt;

    dis.dis(&quot;heapq.nsmallest(d,3)&quot;)

          0 BUILD_SET             24933
          3 JUMP_IF_TRUE_OR_POP   11889
          6 JUMP_FORWARD          28019 (to 28028)
          9 STORE_GLOBAL          27756 (27756)
         12 LOAD_NAME             29811 (29811)
         15 STORE_SLICE+0  
         16 LOAD_CONST            13100 (13100)
         19 STORE_SLICE+1

I see that [`JUMP_IF_TRUE_OR_POP`](http://docs.python.org/library/dis.html#opcode-JUMP_IF_TRUE_OR_POP) etc. are bytecode instructions *(although interestingly, `BUILD_SET` does not appear in this list, though I expect it works as [`BUILD_TUPLE`](http://docs.python.org/library/dis.html#opcode-BUILD_TUPLE))*. I think the numbers on the right-hand-side are memory allocations, and the numbers on the left are [goto](http://en.wikipedia.org/wiki/GOTO) numbers... I notice they *almost* increment by 3 each time (but not quite).

If I wrap `dis.dis(&quot;heapq.nsmallest(d,3)&quot;)` inside a function:

&lt;!-- language: lang-py --&gt;

    def f_heapq_nsmallest(d,n):
        return heapq.nsmallest(d,n)

    dis.dis(&quot;f_heapq(d,3)&quot;)

          0 BUILD_TUPLE            26719
          3 LOAD_NAME              28769 (28769)
          6 JUMP_ABSOLUTE          25640
          9 &lt;44&gt;                                      # what is &lt;44&gt; ?  
         10 DELETE_SLICE+1 
         11 STORE_SLICE+1 

How should I understand the output of dis.dis?

While reading https://en.uncyclopedia.co/wiki/Haskell (and ignoring all the &quot;offensive&quot; stuff), I stumbled upon the following piece of obfuscated code:

    fix$(&lt;$&gt;)&lt;$&gt;(:)&lt;*&gt;((&lt;$&gt;((:[{- thor&#39;s mother -}])&lt;$&gt;))(=&lt;&lt;)&lt;$&gt;(*)&lt;$&gt;(*2))$1

When I run that piece of code in `ghci` (after importing `Data.Function` and `Control.Applicative`), `ghci` prints the list of all powers of 2.

How does this piece of code work?

How does this piece of obfuscated Haskell code work?

I am a newbie for node js. What is the use of express JS? According to my understanding it is used for web projects and has some templates like Jade and CSS. 

Is there anyother extra features in express.js that make it more dominating than node.js?
Which one is better node.js or express.js when it comes to server side coding?
Diff. between Express.js and node.js.

Kindly help. Thanks.

Difference between Node js and express js

I am a newbie for node js. What is the use of express JS? According to my understanding it is used for web projects and has some templates like Jade and CSS.
Is there anyother extra features in express.js that make it more dominating than node.js?
Which one is better node.js or express.js when it comes to server side coding?
Diff. between Express.js and node.js.
Kindly help. Thanks.

Is there a way to add created_at and `updated_at` fields to a mongoose schema, without having to pass them in everytime new `MyModel()` is called?

The `created_at` field would be a date and only added when a document is created.
The `updated_at` field would be updated with new date whenever `save()` is called on a document.

I have tried this in my schema, but the field does not show up unless I explicitly add it:

    var ItemSchema = new Schema({
        name    : { type: String, required: true, trim: true },
        created_at    : { type: Date, required: true, default: Date.now }
    });



add created_at and updated_at fields to mongoose schemas

Before I ask about `app.router` I think I should explain at least what I think happens when working with middleware. To use middleware, the function to use is `app.use()`. When the middleware is being executed, it will either call the next middleware by using `next()` or make it so no more middleware get called. That means that the order in which I place my middleware calls is important, because some middleware depends on other middleware, and some middleware near the end might not even be called.

Today I was working on my application and had my server running in the background. I wanted to make some changes and refresh my page and see the changes immediately. Specifically, I was making changes to my layout. I couldn&#39;t get it to work so I searched Stack&amp;nbsp;Overflow for the answer and found [this question][1]. It says to make sure that `express.static()` is beneath `require(&#39;stylus&#39;)`. But when I was looking at that OP&#39;s code, I saw that he had his `app.router` call at the very end of his middleware calls, and I tried to figure out why that was.

When I made my Express.js application (version 3.0.0rc4), I used the command `express app --sessions --css stylus` and in my app.js file the code came setup with my `app.router` above both the `express.static()` and `require(&#39;stylus&#39;)` calls. So it seems like, if it comes already setup that way, then it should stay that way.

After re-arranging my code so I could see my Stylus changes, it looks like this:

    app.configure(function(){
      //app.set() calls
      //app.use() calls
      //...
      app.use(app.router);
      app.use(require(&#39;stylus&#39;).middleware(__dirname + &#39;/public&#39;));
      app.use(express.static(__dirname + &#39;/public&#39;, {maxAge: 31557600000}));
    });

    app.get(&#39;/&#39;, routes.index);

    app.get(&#39;/test&#39;, function(req, res){
      res.send(&#39;Test&#39;);
    });

So I decided that the first step would be to find out why it is important to even have `app.router` in my code. So I commented it out, started my app and navigated to `/`. It displayed my index page just fine. Hmm, maybe it worked because I was exporting the routing from my routes file (routes.index). So next I navigated to `/test` and it displayed Test on the screen. Haha, OK, I have no idea what `app.router` does. Whether it is included in my code or not, my routing is fine. So I am definitely missing something.

**So Here Is My Question:**

Could somebody please explain what `app.router` does, the importance of it, and where I should place it in my middleware calls? It would also be nice if I got a brief explanation about `express.static()`. As far as I can tell, `express.static()` is a cache of my information, and if the application can&#39;t find the requested page, it will check the cache to see if it exists.

  [1]: https://stackoverflow.com/questions/5612777/stylus-and-express-stylesheets-are-not-re-compiled-when-modified


Node.js / Express.js - How does app.router work?

On a Debian server, I installed Node.js. I understand how to launch an app from putty with this command line:
 
    node /srv/www/MyUserAccount/server/server.js

and get to it on the address `50.51.52.53:8080` (IP and port).

But as soon as I close putty, then I cannot reach the address `50.51.52.53:8080` anymore.

How to make a Node.js application run permanently?

As you can guess, I am a beginner with Linux and Node.js.

How to make a node.js application run permanently?

I am trying to create a middleware that can accept parameters. How can this be done?

example

    app.get(&#39;/hasToBeAdmin&#39;, HasRole(&#39;Admin&#39;), function(req,res){
    
    })
    
    HasRole = function(role, req, res, next){
       if(role != user.role){
          res.redirect(&#39;/NotInRole);
       }
    
       next();
    }

Creating a expressjs middleware that accepts parameters

I&#39;m trying to write a script to download images using node.js. This is what I have so far:

    var maxLength = 10 // 10mb
    var download = function(uri, callback) {
      http.request(uri)
        .on(&#39;response&#39;, function(res) {
          if (res.headers[&#39;content-length&#39;] &gt; maxLength*1024*1024) {
            callback(new Error(&#39;Image too large.&#39;))
          } else if (!~[200, 304].indexOf(res.statusCode)) {
            callback(new Error(&#39;Received an invalid status code.&#39;))
          } else if (!res.headers[&#39;content-type&#39;].match(/image/)) {
            callback(new Error(&#39;Not an image.&#39;))
          } else {
            var body = &#39;&#39;
            res.setEncoding(&#39;binary&#39;)
            res
              .on(&#39;error&#39;, function(err) {
                callback(err)
              })
              .on(&#39;data&#39;, function(chunk) {
                body += chunk
              })
              .on(&#39;end&#39;, function() {
                // What about Windows?!
                var path = &#39;/tmp/&#39; + Math.random().toString().split(&#39;.&#39;).pop()
                fs.writeFile(path, body, &#39;binary&#39;, function(err) {
                  callback(err, path)
                })
              })
          }
        })
        .on(&#39;error&#39;, function(err) {
          callback(err)
        })
        .end();
    }

I, however, want to make this more robust:

1. Are there libraries that do this and do this better?
2. Is there a chance that response headers lie (about length, about content type)?
3. Are there any other status codes I should care about? Should I bother with redirects?
4. I think I read somewhere that `binary` encoding is going to be deprecated. What do I do then?
5. How can I get this to work on windows?
6. Any other ways you can make this script better?

Why: for a feature similar to imgur where users can give me a URL, I download that image, and rehost the image in multiple sizes.

Downloading images with node.js

I&#39;m using node + express and I am just wondering how I can import any file as a string. Lets say I have a txt file all I want is to load it into a variable as such.

    var string = require(&quot;words.txt&quot;);

I am against 

    modules.exports = function(){
    
        var string = &quot;whatever&quot;;
        
        return string;

    }

require file as string

To use MomentJS in views/custom.ejs, what is the correct way (if any)?

 1. Server side

    routes/index etc we can easily use `require(&#39;moment&#39;);` etc and it works fine.
 3. Server Side (EJS views)

    views/custome.ejs, something like `&lt;% var m = require(&#39;moment&#39;); %&gt;` doesn&#39;t work

I am using ExpressJS with EJS as the template engine.

Content Type	Original Author	Original Content on Stackoverflow
Question	vinod	View Question on Stackoverflow
Solution 1 - node.js	defuz	View Answer on Stackoverflow
Solution 2 - node.js	loganfsmyth	View Answer on Stackoverflow
Solution 3 - node.js	Rishav Rastogi	View Answer on Stackoverflow

Difference between Node js and express js

node.js Problem Overview

node.js Solutions

Solution 1 - node.js

Solution 2 - node.js

Solution 3 - node.js

How does this piece of obfuscated Haskell code work?

How should I understand the output of dis.dis?

Attributions