flag.js

//read flag ---- r
/*
const fs = require('fs');
const http= require('http');

http.createServer((req,res)=>{
    console.log("server created");
    fs.open('myNewFile.txt', 'r', (err)=>{
        if(err) throw err;
        console.log('File opened for read');
        return res.end();
    })
}).listen(5405);
*/
//=============================================================

//write flag ---- w
/*
const fs = require('fs');

    fs.open('myNewFile11.txt', 'w', (err, file)=>{
        if(err) {
        console.log('Error', err);
        return;
        }
        console.log('file opened for writing');
    });

*/

//===============================================================

//Read and write flag ----   r+
/*
const fs = require('fs');

    fs.open('myNewFile.txt', 'r+', (err, file)=>{
        if(err) {
        console.log('Error', err);
        return;
        }
        console.log('file opened for reading and writing');
    });
*/

//===========================================================
// exist or not if not then ready for write else throw error file already exist 
/*

const fs = require('fs');

    fs.open('myNewFile10.txt', 'wx', (err, file)=>{
        if(err) {
        console.log('Error', err);
        return;
        }
        console.log('file opened for writing and reading ');
    });

    */

    //===========================================================
// append and read 

const fs = require('fs');

    fs.open('myNewFile12.txt', 'a+', (err, file)=>{
        if(err) {
        console.log('Error', err);
        return;
        }
        console.log('file opened for append and reading ');
    });