AsteroidsListController.js

({
   doInit: function(component, event, helper) {      
      //Fetch the asteroid list from the Apex controller   
      helper.getAsteroidList(component);
   },
   showDetails: function(component, event, helper) {
        //Get data via "data-data" attribute from button (button itself or icon's parentNode)
        var url = event.target.getAttribute("data-data") || event.target.parentNode.getAttribute("data-data")       
   },
    
    searchAsteroids: function(component, event, helper) {
      helper.getAsteroidList(component);
	}
})