ag-grid: is there a way to trigger event when clear range selection

If I understood correctly by selected range are cleared I am assuming user is randomly clicking on any cell in the grid thus only one cell is getting highligheted and range is cleared. for this there is no separate event so you have to check the CellRange object in that case. below logic you can use inside rangeSelectionChanged event

onRangeSelectionChanged(event) {
...
...

//lets check here if selection is cleared by user or not
var cellRanges = this.gridApi.getCellRanges(); // this gives the cellrange object.
var startRowIndex = cellRanges[0].startRow.rowIndex;
var endRowIndex = cellRanges[0].endRow.rowIndex;
var NumberOfColumns = cellRanges[0].columns.length;

//cellRange.length shows how many different ranges user has selected in Grid

if(startRowIndex === endRowIndex && NumberOfColumns ===1 && cellRanges.length<2)
{
//do your processing here 
}