code: function(filterGroup) {
      const filters = filterGroup.filters.map((filterDef) => {
        const condition = filterDef.condition;
        if (Array.isArray(condition)) {
          return WfsPermalinkService.or_(condition.map(cond => equalTo(filterDef.property, cond)));
        } else {
          return equalTo(filterDef.property, condition);
        }
      });
      return WfsPermalinkService.and_(filters);
    }
docs: The function
  @param {WfsPermalinkFilterGroup} filterGroup The filter
  @returns {import("ol/format/filter/Filter.js").default} The return