Node JS in details Example
Events and Event Loop,Work with File System,
Example:1
var fs = require("fs");
fs.readFile('input.txt', function (err, data) {
if (err) return console.error(err);
console.log(data.toString());
});
console.log("Program Ended");
Example:2
var fs = require("fs");
var data = fs.readFileSync('input.txt');
console.log(data.toString());
console.log("Program Ended");
Example:3
function sayHello(name)
{
console.log( "Hello" +name);
}
// Now call above function after 2 seconds
sayHello('james');
Example:4
var globalvar1 = 25;
var z = 20;
function test(x, y)
{
var z = 10;
console.log('x: ' + x);
console.log('y: ' + y);
console.log('z: ' + z);
console.log('globalvar1: ' + globalvar1);
}
test(11, 22);
Example:5
var number=7;
if(number%2==0)
{
console.log("Even Number");
}
else
{
console.log("odd number");
}
Example:6
function a_function(fn) {
console.log('before');
// call the call back function. It requires 2 arguments.
var result = fn(4, 5);
console.log('after');
return result;
}
function test() {
var result = a_function(function(x, y) {
var value = x + y;
console.log(value);
return value;
});
console.log('result: ' + result);
}
test();
Example:7
function test(container)
{
var idx = 0;
while (idx < container.length)
{
console.log('item: ' + container[idx]);
idx += 1;
}
}
var container = [11, 22, 33, ];
test(container);
Example:8
// Get different parts of the URL
// using object properties
const url = require('url');
// URL address
const address ='https://smarteportal.blogspot.com';
// Call parse() method using url module
let urlObject = url.parse(address, true);
console.log('Url host');
// Returns 'smarteportal.blogspot.com'
console.log(urlObject.host);
console.log('Url pathname');
// Returns '/projects'
console.log(urlObject.pathname);
console.log('Url search');
// Returns '?sort=newest&lang=nodejs'
console.log(urlObject.search);
// Get query data as an object
// Returns an object:
// { sort: 'newest', lang: 'nodejs' }
let queryData = urlObject.query;
console.log(queryData);
console.log('Url query object');
// Returns 'nodejs'
console.log(queryData.lang);
Example:9
const http = require('http')
const hostname = '127.0.0.1'
const port = 8000
const server = http.createServer((req, res) =>
{
res.statusCode = 200
res.setHeader('Content-Type', 'text/plain')
res.end('Hello World\n')
})
server.listen(port, hostname, () =>
{
console.log(`Server running at http://${hostname}:${port}/`)
})