Extend Ajax beforeSend method

Submitted by Dmitro on

Here we extend system Drupal.Ajax.prototype.beforeSend() method. We set progress variable according to data attribute. 

let ajaxBeforeSendOriginal = Drupal.Ajax.prototype.beforeSend;  
// Extend Drupal.Ajax.prototype.beforeSend.  
Drupal.Ajax.prototype.beforeSend = function (xmlhttprequest, options) {  
  // Set progress variable according to data attribute.  
  this.progress.type = $(this.element).data("ajax-progress") || 
  this.progress.type;  ajaxBeforeSendOriginal.call(this, xmlhttprequest, options);  
};