js calback function code example

Example 1: what are callback functions

// A function which accepts another function as an argument
// (and will automatically invoke that function when it completes - note that there is no explicit call to callbackFunction)
funct printANumber(int number, funct callbackFunction) {
    printout("The number you provided is: " + number);
}

// a function which we will use in a driver function as a callback function
funct printFinishMessage() {
    printout("I have finished printing numbers.");
}

// Driver method
funct event() {
   printANumber(6, printFinishMessage);
}

Example 2: callback function

function createQuote(quote, callback){ 
  var myQuote = "Like I always say, " + quote;
  callback(myQuote); // 2
}

function logQuote(quote){
  console.log(quote);
}

createQuote("eat your vegetables!", logQuote); // 1

// Result in console: 
// Like I always say, eat your vegetables!