javascript callback

1// *** JS GetPosts Callback ***
2
3    run.addEventListener('click', () => {
4        window.lib.getPosts((error, articles) => {
5          	return (error ? console.log(error) : console.log(articles));
6            /* Alternate syntax
7          	 if (error) {
8                 console.log(error);
9             }
10             for (elem of articles) {
11                 console.log(elem);
12            }; // => console.log(articles); similarly works
13            /*
14        });
15    })

1/*
2A callback function is a function passed into another function
3as an argument, which is then invoked inside the outer function
4to complete some kind of routine or action. 
5*/
6function greeting(name) {
7  alert('Hello ' + name);
8}
9
10function processUserInput(callback) {
11  var name = prompt('Please enter your name.');
12  callback(name);
13}
14
15processUserInput(greeting);
16// The above example is a synchronous callback, as it is executed immediately.

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// Create a callback in the probs, in this case we call it 'callback'
2function newCallback(callback) {
3  callback('This can be any value you want to return')
4}
5
6// Do something with callback (in this case, we console log it)
7function actionAferCallback (callbackData) {
8  console.log(callbackData)
9}
10
11// Function that asks for a callback from the newCallback function, then parses the value to actionAferCallback
12function requestCallback() {
13  newCallback(actionAferCallback)
14}