In my project I have to create my own multiple sorting and multiple grouping dialogs. Basically user can choose which columns should be included, select order and direction of operation. 

For multiple sorting I use this function and it works

     .igGridSorting( "sortMultiple", [exprs:array] );

The problem is now with grouiping. Is there any function which will behave similary? I mean executing with array of grouping expressions (which define columns to group by, order of grouping and direction of grouping (acs / desc)) as parameter?

In the documentation I have found:

     .igGridGroupBy( "groupByColumns" );

The description is "Adds a column to the group by columns list, executes the group by operation and updates the view."

But there is nothing about how add this columns.