JS Helper Controller

({  
   FilterRecords: function(component) {  
     //data showing in table  
     var data = component.get("v.data");  
     // all data featched from apex when component loaded  
     var allData = component.get("v.UnfilteredData");  
     //Search tems  
     var searchKey = component.get("v.filter");  
     // check is data is not undefined and its lenght is greater than 0  
     if(data!=undefined || data.length>0){  
       // filter method create a new array tha pass the test (provided as function)  
       var filtereddata = allData.filter(word => (!searchKey) || word.Name.toLowerCase().indexOf(searchKey.toLowerCase()) > -1);  
       console.log('** '+filtereddata);  
     }  
     // set new filtered array value to data showing in the table.  
     component.set("v.data", filtereddata);  
     // check if searchKey is blank  
     if(searchKey==''){  
       // set unfiltered data to data in the table.  
       component.set("v.data",component.get("v.UnfilteredData"));  
     }  
   }  
 })