JSFiddle - React, Tailwind, and code Playground

JavaScript

var list = ['obj1', 'obj2', 'obj3', 'obj4', 'obj5'];
var callback = function() {
  console.log("done");
};
var requests = [];

  for(i = 0; i < list.length; i++) {
    requests.push($.ajax({
      url: 'url',
      success: function() {
        console.log('suc');
      }
    }));
  }

$.when.apply(undefined, requests).then(function(results){callback()});