Ajax request on Resources is possible?

[Digofbbr]

So, on page load i need to call a jquery ajax to return an array with Resource values, is it possible? if yes, could you give me an example? I'm doing the following but without success

    let ec = new EventCalendar(document.getElementById('ec'), {
      view: 'resourceTimelineMonth',
      events: [
      ],
      resources: that.getAllServices(project_id),
    });
    
    getAllServices(project_id){

      $.ajax({
        url: '/dashboard/construction_management/timetable/all_services/' + project_id,
        type: "GET",
        dataType: 'json',
        success: function(data){
          return data
        },
        error: function(xhr, status, error){
          console.log(error)
        }
      })
    
    

data returns an array from my rails backend