combineBboxAndFilter(geometryName, extent, srsName, filter) {
    const bboxFilter = bboxFilterFn(geometryName, extent, srsName);
    if (filter) {
      // if bbox and filter are both set, combine the two into a single filter
      return andFilterFn(filter, bboxFilter);
    }
    return bboxFilter;
  }
Create a bbox filter and combine it with another optional filter.

@param {!string} geometryName Geometry name to use.
@param {!import("../extent.js").Extent} extent Extent.
@param {string} [srsName] SRS name. No srsName attribute will be
   set on geometries when this is not provided.
@param {import("./filter/Filter.js").default} [filter] Filter condition.
@return {import("./filter/Filter.js").default} The filter.