function addFacetRefinement(facet, value) {
    if (!this.isConjunctiveFacet(facet)) {
      throw new Error(facet + ' is not defined in the facets attribute of the helper configuration');
    }
    if (RefinementList.isRefined(this.facetsRefinements, facet, value)) return this;

    return this.setQueryParameters({
      facetsRefinements: RefinementList.addRefinement(this.facetsRefinements, facet, value)
    });
  }