ref => {
   let query : Query = ref;
   query = query.where('isPublished', '==', true);
   query = query.where('domain', '==', filters.domain);
   query = query.orderBy('displayName', 'asc');
   return query;
 });   

 ref => {
   let query: Query = ref;
   query = query.where('isPublished', '==', filters.isPublished);
   query = query.where('channel', '==', filters.channel);
   query = query.where('domain', '==', filters.domain);
   query = query.orderBy('published', 'desc');
   if (lastItem) {
     query = query.startAfter(lastItem.doc);
   }
   query = query.limit(20);
   return query;
 }

	return (colRef: Query) => {															// return a Query-function
		if (query.where)
			asArray<IWhere>(query.where)
				.forEach(qry => colRef = colRef.where(qry.fieldPath, qry.opStr as WhereFilterOp, qry.value));

		if (query.orderBy)
			asArray(query.orderBy)
				.forEach(order => colRef = colRef.orderBy(order.fieldPath, order.directionStr));

		if (isNumeric(query.limitTo))
			colRef = colRef.limit(query.limitTo as number);

		return colRef;
	}

				.forEach(order => colRef = colRef.orderBy(order.fieldPath, order.directionStr));