Implementing a trigger event for hierarchical datagrid expand

[Mil4n0r]

Checklist

• Build process is done without errors. All tests pass in the /lib directory.
• Self-reviewed the code before submitting.
• Meets accessibility standards.
• Added/updated documentation to /website as needed.
• Added/updated tests as needed.

Purpose
The idea of the change is being able to handle highly nested data in a more appropiate way. With the previous API we were forcing the users to load the whole dataset inside the rows item from the DxcDatagrid. Which is not feasible most of the time due to big performance impact.

Description
In order to achieve that purpose, a new prop has been added to the component, loadChildren?: (expandChildren: HierarchyGridRow) => HierarchyGridRow[] | Promise<HierarchyGridRow[]>;. As its name says, it is an additional way of setting the children for a hierarchical data, this data can come from any type of source and is specially useful for lazy loading purposes (until you click on the expand button, the children data for that node is not processed).

Additional context
There are still some edge cases which have to be reviewed as well as including additional documentation, testing and stories for the component.

[Mil4n0r]

Should we add a mechanism to display a spinner while the data is being loaded when setting the loadChildren function?

[Jialecl]

Should we add a mechanism to display a spinner while the data is being loaded when setting the loadChildren function?

They are able to use the Spinner component easily without any mechanism from the datagrid

[Jialecl]

We need to discuss about this approach because I find issues with delays in case the children are not returned instantly.

[Jialecl]

Updates missing in the documentation.

[Jialecl]

There are still problems with the selection.
You can select other rows or the select all row and it won't be taken into account once the rows are rendered.
Maybe we should consider a global state for all the checkboxes instead of a row state.

[Jialecl]

There is just one small bug I was able to reproduce:

It seems to be related to collapsed grandchildren while selected are stored in the selected row set and stayed on the list after unselected.