diff --git a/query-planner-js/src/buildQueryPlan.ts b/query-planner-js/src/buildQueryPlan.ts
index e5b340931..c68ce109c 100644
--- a/query-planner-js/src/buildQueryPlan.ts
+++ b/query-planner-js/src/buildQueryPlan.ts
@@ -876,7 +876,7 @@ class FetchGroup {
     return group;
   }
 
-  get dependentGroups() {
+  get dependentGroups(): FetchGroup[] {
     return [
       ...Object.values(this.dependentGroupsByService),
       ...this.otherDependentGroups,