How to create Node.js Module

How to create Node.js Module

Node.js has a set of modules that are built in.Example of these built-in modules are.

  1.http-creates http server.
  2.fs-to handle file system.
  3.assert-provide assertions.

Example code on how to use http module.

Below code creates a server to displays "Programming in Node.js"  string.

var http=require('http');

http.createServer(function(req,res)

{

res.writeHead(200,{'Content-type':'text/plain'});

res.write("Programming in Node.js");

res.end();

}).listen(8080);

Apart from inbuilt node.js modules,developers can create their own modules and use them anywhere in the project and this makes the code reusable.

Creating a node.js  module to return current date and time

var op=require('os');

exports.myOperatingSystem=function()

{

return op.platform();

}

save above code as "firstmodule.js"

var http=require('http');

var os=require('./firstmodule');

http.createServer(function(req,res)

{

res.writeHead(200,{'Content-type':'text/html'});

res.write("My Operating system is:" + os.myOperatingSystem() );

res.end();

}).listen(8080);

save the code as" firstscript.js"

Open a command prompt and run the file firstscript file.

Output

NB:

Any time you make changes to a node.js file, the changes don't reflect automatically to the server.To avoid restarting the server whenever making changes,

Try to Install 

1. Nodemon  or 

2.Supervisor