The data loading methods are built with jQuery.ajax and are integrated into the jQuery edition, so the onLoadSuccess,onLoadError,onBeforeLoad events are available.
When using react, you are building a data-driven application. All you need to do is to provide the data, you don't need to worry about the DOM operations. The EasyUI for React has no data operation methods because these are not needed. You can use fetch or axios to load your data from server.
Please look at these example
https://www.jeasyui.com/demo-react/main/index.php?plugin=DataGrid&theme=material-teal&dir=ltr&pitem=&sort=asc. All the crud operations are made by modifying the data in the state.