Through Callbacks
const fs =require('fs');
console.log('Before');
fs.readFile('f1.txt',cb1);
function cb1(err,data){
if(err)
{
console.log(error);
}
else
{
console.log(" "+data);
fs.readFile('f2.txt',cb2);
}
}
function cb2(err,data){
if(err)
{
console.log(err);
}
else
{
console.log(" "+data);
fs.readFile('f3.txt',cb3);
}
}
function cb3(err,data){
if(err)
{
console.log(err);
}
else
{
console.log(" "+data);
}
}
console.log('After');
//π ans ->
// Before
// After
// this is file 1
// this is file 2
// this is file 3
Through Promise
const fs =require('fs');
console.log('Before');
let f1p=fs.promises.readFile('f1.txt');
f1p.then(cb1);
function cb1(data){
console.log("File data->"+data);
let f2p=fs.promises.readFile('f2.txt');
f2p.then(cb2);
}
function cb2(data)
{
console.log("File data->"+data);
let f3p=fs.promises.readFile('f3.txt');
f3p.then(cb3);
}
function cb3(data){
console.log("File data->"+data);
}
console.log('After');
//π ans ->
// Before
// After
// File data->this is file 1
// File data->this is file 2
// File data->this is file 3
πHandwritten Notes:
https://github.com/pushanverma/notes/blob/main/webd/Serially%20in%20Js%20.pdf
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