diff --git a/src/Util/FilterUtil.ts b/src/Util/FilterUtil.ts
index dd54b9ec1..13534916b 100644
--- a/src/Util/FilterUtil.ts
+++ b/src/Util/FilterUtil.ts
@@ -94,7 +94,7 @@ class FilterUtil {
     }
     let matchesFilter: boolean = true;
     const operator: Operator = filter[0];
-    const isNestedFilter = FilterUtil.nestingOperators.includes[operator];
+    const isNestedFilter = FilterUtil.nestingOperators.includes(operator);
 
     if (isNestedFilter) {
       matchesFilter = FilterUtil.handleNestedFilter(filter, feature);