fix: the rest datasource should not reload if the query is undefined #211

source/components/datatable/datasource/rest.mjs

@@ -386,7 +386,10 @@ function initFilter() {
 		);
 
 	this[filterObserverSymbol] = new Observer(() => {
-		const query = filterControl.getOption("query", undefined);
+		const query = filterControl.getOption("query");
+		if ( query===undefined) {
+			return;
+		}
 		this.setParameters({ query: query });
 		this.fetch()
 			.then((response) => {