Get All File in Folder Using JSOM

function ViewAllFiles()

{

var context = new SP.ClientContext.get_current();

var web = context.get_web();

var list = web.get_lists().getByTitle('NGO-Document');

var query = SP.CamlQuery.createAllItemsQuery();

query.set_folderServerRelativeUrl('/NGO-Document/NGOFolder');

allItems = list.getItems(query);

context.load(allItems, 'Include(Title, ContentType, File)');

context.executeQueryAsync(Function.createDelegate(this, this.success),   Function.createDelegate(this, this.failed));

}

 

function success()

{

debugger;

  var fileUrls = "";

  var ListEnumerator = this.allItems.getEnumerator();

   while(ListEnumerator.moveNext())

   {

    var currentItem = ListEnumerator.get_current();

    var _contentType = currentItem.get_contentType();

     if(_contentType.get_name() != "Folder")

       {

        var File = currentItem.get_file();

        if(File != null)

          {

           fileUrls += File.get_serverRelativeUrl() + '\n';

          }

       }

   }

  alert(fileUrls);

}

function failed(sender, args) {

  alert("failed. Message:" + args.get_message());

}