Sets/gets the field name of the column where the filtering expression is placed.

 gridExpressionTree.fieldName = 'Column Field';

let columnField = expressionTree.fieldName;

Sets/gets the filtering operands.

const gridExpressionsTree = new FilteringExpressionsTree(FilteringLogic.And);
const expression = [
{
  condition: IgxStringFilteringOperand.instance().condition('contains'),
  fieldName: 'Column Field',
  searchVal: 'Value',
  ignoreCase: false
}];
gridExpressionsTree.filteringOperands.push(expression);
this.grid.filteringExpressionsTree = gridExpressionsTree;

let filteringOperands = gridExpressionsTree.filteringOperands;

Sets/gets the operator.

gridExpressionsTree.operator = FilteringLogic.And;

let operator = gridExpressionsTree.operator;