what is Node.js, how to Install and work.

 Node.js is an open source server environment and run JavaScript on the server.

1. install Node.js  - install from official site  https://nodejs.org.

2. how to create and run file

step 1) make file with extension .js

step 2) save the file to other drive

step 3) open node.js command prompt 

step 4) change directory in command eg: E: for e directory , D: for d directory

step 5) then subdirectory/folder = cd E:\nodejsfolder

step 6) type node filename.js

3. writing hello world using node.js

add below code to abc.js 

var http = require("http");

http.createServer(function (request, response) {

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

   response.end('Hello World\n');

}).listen(8081);

console.log('Server running at http://127.0.0.1:8081/');

open node.js command prompt(not normal command prompt) and type node abc.js

command prompt shows message "Server running at http://127.0.0.1:8081/"

go to this server from browser and check link http://127.0.0.1:8081/ , you will see "hello world"

if you close command prompt , server also close. to continuous on server add 'forget' module

4. install require packages using command.

npm install name.

for example - npm install ws --> to add websocket

remember to run use 'node filename.js' from command

4. create server 

var http = require("http");

var server = http.createServer(function(){

   console.log("Hello");

});

server.listen(3000);

 now go to browser and open localhost:3000 & then check command prompt it show hello means server started.

please comment if any query.