waitData

eventual result of an asynchronous operation ('promise' object) for the loaded data

Example

var grid = webix.ui({
    view:"datatable", //any data object
    url:"data.php",
});
 
grid.waitData.then(function(){
    // when we have data, do some actions
    grid.select(grid.getFirstId());
});

The ultimate advantage of Promise objects is that they allow treating the result of asynchronous operations without callbacks.