callback function

1function startWith(message, callback){
2	console.log("Clearly written messages is: " + message);
3  
4  	//check if the callback variable is a function..
5  	if(typeof callback == "function"){
6    	callback(); //execute function if function is truly a function.
7    }
8}
9//finally execute function at the end 
10startWith("This Messsage", function mySpecialCallback(){
11	console.log("Message from callback function");
12})

1function greeting(name) {
2  alert('Hello ' + name);
3}
4
5function processUserInput(callback) {
6  var name = prompt('Please enter your name.');
7  callback(name);
8}
9
10processUserInput(greeting);

1// A function which accepts another function as an argument
2// (and will automatically invoke that function when it completes - note that there is no explicit call to callbackFunction)
3funct printANumber(int number, funct callbackFunction) {
4    printout("The number you provided is: " + number);
5}
6
7// a function which we will use in a driver function as a callback function
8funct printFinishMessage() {
9    printout("I have finished printing numbers.");
10}
11
12// Driver method
13funct event() {
14   printANumber(6, printFinishMessage);
15}
16

1//Callback functions - are functions that are called AFTER something happened
2
3  const foo = (number, callbackFunction) => {
4    //first 
5    console.log(number)
6    
7    //second - runs AFTER console.log() happened
8    callbackFunction()
9  }
10  

1function createQuote(quote, callback){ 
2  var myQuote = "Like I always say, " + quote;
3  callback(myQuote); // 2
4}
5
6function logQuote(quote){
7  console.log(quote);
8}
9
10createQuote("eat your vegetables!", logQuote); // 1
11
12// Result in console: 
13// Like I always say, eat your vegetables!

1const ironMan = withGloves(withBoots(withArmor(withHelmet(TonyStark))));