Why we need http module installed to run our node js application?

Question

I have found so many sources for now when the first application shows this line

 var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World!');
}).listen(8080); 

Just being geek, my Question is why we need server/port to listen our requests for our node js applications? Why can't we run as localhost/application_name instead? Why we need that?

Can anyone elobarate please?

Answer 1

Node.js® is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.

So if you want an application which only work with bash you don't need any http modules.

Browsers use HTTP. So if you want to develop a web application you need to use that protocol. If you run your project on 80 port you can use it like localhost/my_application.

Simple app.js

var result = doSomething();
functions doSomething(){
    return "This the result";
}
console.log(result);

You can call it from bash. node app.js. But it just work and stop.

But if you want to serve this structure to WWW (which is using HTTP) you need to create server. http is a great and simple module for creating servers with node.js.

You can use other js files with using require.

app.js

var result = doSomething();
functions doSomething(){
    return "This the result";
}
module.exports = result;

server.js

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    var result = require('app.js');
    res.end(result);
}).listen(80);

Now you can run your server. node server.js