//Call back functions -Any function that is passed as an argument to another function is known as Callback function.
function printFirstname(firstname,cb,cb2)
{
//cb recieves Lastname function
//cb2 recieves printage function
console.log(firstname);
cb("Verma")
cb2(22);
}
function printLastname(lastname)
{
console.log(lastname);
}
function printAge(age)
{
console.log(age)
}
printFirstname("Pushan",printLastname,printAge);
//👉ans->
//Pushan
//Verma
//22
2nd example:
const fs =require('fs');
console.log("before");
// let data =fs.readFileSync('f1.txt');
fs.readFile('f1.txt',cb);
fs.readFile('f2.txt',cb2);
function cb(err,data)
{
if(err)
{
console.log(err);
}
console.log(" "+data);
}
function cb2(err,data)
{
if(err)
{
console.log(err);
}
console.log(" "+data);
}
console.log("after");
// 👉 ans ->
// before
// after
// this is file 2
// this is file 1
📌HandWritten Notes:
https://github.com/pushanverma/notes/blob/main/webd/Callbacks%20in%20Js%20.pdf
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