Defination

*Any function which is taking another function as a argument that function is called HOF.
*Function are called HOF only if it takes minimum one function as a argument.
*Array.map, Array.filter, and Array.reduce are common higher-order functions that take a callback function as an argument.

syntax:

function myfunction(name,city){

}
myfunction(function(){},function(){});

Example

function fun(callback1, callback2) {
callback1();
callback2();
}

// Example functions to pass as arguments
function sayHello() {
console.log('Hello!');
}

function sayGoodbye() {
console.log('Goodbye!');
}

// Calling 'fun' with two functions as arguments
fun(sayHello, sayGoodbye);

// Output:
// Hello!
// Goodbye!

Not a Higher order function

function f1(x){
--------------------
}
f1(100);
*Because it does not take function as a argument.