The example provide in the link seems to be a JavaScript one - https://www.ag-grid.com/javascript-grid-tree/?framework=angular#gsc.tab=0.
Can this be integrated with Angular? What are the tings taken care of in warping up in angular interface using ag-Grid?
Check the documentation for ag-Grid, it shows how to get the grid integrated with angular.
ag-Grid Angular 2
All the features work in Angular 2 - the examples for the different features are in JavaScript only because the grid supports so many frameworks, the team would find it impossible to demonstrate every feature in every framework.