Callback Functions

A callback function is a function which is passed as an argument to another function.

e.g. function kind(){

console.log("I'm kind");

}

function rude(){

console.log("I'm rude");

}

function fun(a, b){

a();//calls kind()

b();//calls rude()

}

fun(kind, rude);

//Output:

I'm kind

I'm rude

Here, kind and rude are callback functions because they are passed as arguments to another function named as fun.

And fun is called a higher order function because it accepts functions (kind and rude) as parameters.