[JS] How to delay ajax one by one in loop

Bahasa indonesia: Bagaimana eksekusi ajax satu per satu di Loop

<div id="demo"></div>
<script>
/
* Define global variable
* @var {int} indexLoop global loop indexer
* @var {int} lastLoop global last iteration for global loop indexer from loop initializer
* @var {array} queueLoop global array to be processed from ajax
* @var {array} arrayLoop define array to be proccesed
*/

var indexLoop = 0,
lastLoop = 0,
queueLoop = [],
arrayLoop = ['apple', 'melon', 'watermelon', 'grapes'];

for (var i = 0; i < arrayLoop.length; i++) {
queueLoop.push(arrayLoop[i]);
if (i == arrayLoop.length - 1) {
lastLoop = i + 1;
ajaxLoop(function () {
var b = document.createElement('b');
b.innerHTML = 'Processing all item ' + indexLoop + ' of ' + lastLoop + ' succedeed<br/>';
document.getElementById('demo').appendChild(b);
});
}
}
/**
* Initialize global ajaxLoop function
* @param {function} lastFunction function to be executed on last iteration
*/
function ajaxLoop(lastFunction) {
if (indexLoop < lastLoop) {
$.ajax({
url: 'https://reqres.in/api/users?page=' + (indexLoop + 1),
beforeSend: function () {
var b = document.createElement('b');
b.innerHTML = 'Processing item ' + indexLoop + ' of ' + lastLoop + '<br/>';
document.getElementById('demo').appendChild(b);
},
success: function (response) {
var b = document.createElement('b');
b.innerHTML = 'Processed item success ' + this.url.split('=')[1] + ' of ' + lastLoop + '<br/>';
document.getElementById('demo').appendChild(b);
},
error: function () {
var b = document.createElement('b');
b.innerHTML = 'Processed item error ' + this.url.split('=')[1] + ' of ' + lastLoop + '<br/>';
document.getElementById('demo').appendChild(b);
},
complete: function () {
var b = document.createElement('b');
b.innerHTML = 'Processed item complete ' + this.url.split('=')[1] + ' of ' + lastLoop + '<br/>';
document.getElementById('demo').appendChild(b);
}
});

indexLoop++;
ajaxLoop();
if (indexLoop == queueLoop.length) {
if (typeof lastFunction == 'function') {
lastFunction();
/
reseting global indexer */
indexLoop = 0;
}
}
}
}
</script>

preview

Delay ajax in loop