angular ui-grid how to use onRegisterApi in gridOptions

Question

I have a editable table with extra rows .columnDefs. I added a grid api to table to get alert when something was change:

$scope.gridOptions.onRegisterApi = function (gridApi) {
        //set gridApi on scope
        $scope.gridApi = gridApi;
        gridApi.edit.on.afterCellEdit($scope, function (rowEntity, colDef, newValue, oldValue) {
            if (newValue !== oldValue) {
                alert('edited row id:' + rowEntity.id + ' Column:' + colDef.name + ' newValue:' + newValue + ' oldValue:' + oldValue);
            }
        });
    };

I don't know how to use it in columnDefs. I tried $scope.gridOptions.columnDefs.onRegisterApi = function (gridApi) {} But it isn't work. I have to get information what was changed in this sub rows.

Solution

$scope.gridOptions.columnDefs.onRegisterApi = function (gridApi) ... won't work, because onRegisterApi is not a property of columnDefs - it belongs directly in gridOptions.

If you want to only watch changes for a particular row / column or some such combination, filter by their name(s) in the handler function.