Trying to get the Column info from sorting

I am trying to track onSortChanged and get the Column info from that sort change event so that I can store that column and its direction of sort in the database.

I am having trouble getting the info from the onSortChanged event though, and I feel like I must not understand exactly what I should be accessing from it?

This is my code:

in gridOptions:

defaultColDef: {
            floatingFilter: true,
            filter: 'agTextColumnFilter',
            filterParams: {
              applyMiniFilterWhileTyping: true,
            },
            resizable: true,
            cellStyle: function (params) {
              return {'font-size': '14px'};
            },
            width: 120,
            sortable: true,
            sortingOrder: ['desc', 'asc', null],
          },
          rowData: this.invoiceList[0].invoiceList,
          rowDragManaged: false,
          animateRows: true,
          components: {
            invoiceCellRenderer: InvoiceCellRenderer
          },
          onSelectionChanged: (event) => this.selectionChanged(event),
          onSortChanged: (params) => this.sortChanged(params),

        }

on sort changed function:

sortChanged(event)
  {
    console.log('event', event);

    var column = event.api.getColId;
    var col = event.columnApi.getColumn();

    console.log('invoicelist api', this.invoiceListGridApi);

    var sort = this.invoiceListGridApi.getSortModel();

    console.log('1', this.invoiceListColumnDefinitions);
    console.log('2', sort);
    console.log('3', col);

    console.log('column', event.api);

  }

All my attempts to access the colId or to getColDef is undefined.

If I try to get access to the api of the invoiceListGridOptions or the api of the invoiceListColumnDefinitions, that is also undefined.

I don’t know what I’m doing wrong?

Any tips would be appreciated.