How to use the forest-express.BaseOperatorDateParser function in forest-express

function ValueStatGetter(model, params, options) {
  const OPERATORS = new Operators(options);

  this.operatorDateParser = new BaseOperatorDateParser({
    operators: OPERATORS,
    timezone: params.timezone,
  });

  const schema = Schemas.schemas[model.name];
  function getAggregate() {
    return params.aggregate.toLowerCase();
  }

  function getAggregateField() {
    // NOTICE: As MySQL cannot support COUNT(table_name.*) syntax, fieldName cannot be '*'.
    const fieldName = params.aggregate_field
      || schema.primaryKeys[0]
      || schema.fields[0].field;
    return `${schema.name}.${Orm.getColumnName(schema, fieldName)}`;
  }

if (value === 'false') { return false; }
    return typeof value === 'boolean' ? value : null;
  };
  const parseString = (value) => {
    // NOTICE: Check if the value is a real ObjectID. By default, the isValid method returns true
    //         for a random string with length 12 (example: 'Black Friday').
    const { ObjectId } = options.mongoose.Types;
    if (ObjectId.isValid(value) && ObjectId(value).toString() === value) {
      return ObjectId(value);
    }
    return value;
  };
  const parseArray = (value) => ({ $size: value });
  const parseOther = (value) => value;

  this.operatorDateParser = new BaseOperatorDateParser({
    operators: { GTE: '$gte', LTE: '$lte' },
    timezone,
  });

  this.perform = async (filtersString) => BaseFiltersParser
    .perform(filtersString, this.formatAggregation, this.formatCondition);

  this.formatAggregation = async (aggregator, formatedConditions) => {
    const aggregatorOperator = this.formatAggregatorOperator(aggregator);
    return { [aggregatorOperator]: formatedConditions };
  };

  this.formatCondition = async (condition) => {
    if (_.isEmpty(condition)) {
      throw new InvalidFiltersFormatError('Empty condition in filter');
    }

function FiltersParser(modelSchema, timezone, options) {
  this.OPERATORS = new Operators(options);
  this.operatorDateParser = new BaseOperatorDateParser({ operators: this.OPERATORS, timezone });

  this.perform = async (filtersString) =>
    BaseFiltersParser.perform(filtersString, this.formatAggregation, this.formatCondition);

  this.formatAggregation = async (aggregator, formatedConditions) => {
    const aggregatorOperator = this.formatAggregatorOperator(aggregator);
    return { [aggregatorOperator]: formatedConditions };
  };

  this.formatCondition = async (condition) => {
    const formatedField = this.formatField(condition.field);

    if (this.operatorDateParser.isDateOperator(condition.operator)) {
      return {
        [formatedField]: this.operatorDateParser
          .getDateFilter(condition.operator, condition.value),