/// <summary>
/// Create a facet field parameter
/// </summary>
/// <param name="documentSearch">Document search engine</param>
/// <param name="conditional">Conditional to add parameter</param>
/// <param name="fieldExpression">Expression used to find field name</param>
/// <param name="instance">Instance of facet ready to configure</param>
/// <returns>Document search engine</returns>
public static DocumentSearch <TDocument> FacetFieldIf <TDocument>(this DocumentSearch <TDocument> documentSearch, Func <bool> conditional, Expression <Func <TDocument, object> > fieldExpression, Action <IFacetFieldParameter <TDocument> > instance = null)
where TDocument : Document
{
Checker.IsNull(conditional);
if (conditional.Invoke())
{
documentSearch.FacetField(fieldExpression, instance);
}
return(documentSearch);
}