checkVariable.js

var DeferredHelper = {
  objectVariableIsSet: function(object, variableName) {
    var dfd = $.Deferred();
 
    var interval = setInterval(function() {
      if (object[variableName] !== undefined) {
        clearInterval(interval);
        console.log('objectVariableIsSet');
        dfd.resolve()
      }
    }, 10);
 
    return dfd.promise();
  },
 
  arrayContainsElements: function(array) {
    var dfd = $.Deferred();
 
    var interval = setInterval(function() {
      if (array.length > 0) {
        clearInterval(interval);
        console.log('arrayContainsElements');
        dfd.resolve()
      }
    }, 10);
 
    return dfd.promise();
  }
}
 
var executeThis = function() {
  console.log('ok!');
}
 
var object = {};
object.var = undefined;
var array = [];
 
$.when(DeferredHelper.arrayContainsElements(array)).then(executeThis);
$.when(DeferredHelper.objectVariableIsSet(object, 'var')).then(executeThis);
 
setTimeout(function() {
  object.var = 2;
  array.push(2);
  array.push(3);
}, 2000);