gridExpressionsTree.entity = 'Entity A';

let entity = gridExpressionsTree.entity;

gridExpressionTree.fieldName = 'Column Field';

let columnField = expressionTree.fieldName;

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;

gridExpressionsTree.operator = FilteringLogic.And;

let operator = gridExpressionsTree.operator;

gridExpressionsTree.returnFields = ['Column Field 1', 'Column Field 2'];

let returnFields = gridExpressionsTree.returnFields;

gridExpressionTree.type = FilteringExpressionsTree.Advanced;

let type = expressionTree.type;

let filteringExpression = gridExpressionTree.find('Column Field');

let filteringExpressionIndex = gridExpressionTree.findIndex('Column Field');