diff --git a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
index b95a4fa6e0e..ddea339cf17 100644
--- a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
@@ -72,7 +72,7 @@ export class {{classname}} {
 {{#hasQueryParams}}
         let queryParameters = {};
 {{#queryParams}}
-        {{#isListContainer}}
+        {{#isArray}}
         if ({{paramName}}) {
         {{#isCollectionFormatMulti}}
             {{paramName}}.forEach((element) => {
@@ -83,8 +83,8 @@ export class {{classname}} {
             queryParameters['{{baseName}}'] = {{paramName}}.join(COLLECTION_FORMATS['{{collectionFormat}}']);
         {{/isCollectionFormatMulti}}
         }
-        {{/isListContainer}}
-        {{^isListContainer}}
+        {{/isArray}}
+        {{^isArray}}
         if ({{paramName}} !== undefined && {{paramName}} !== null) {
         {{#isDateTime}}
             queryParameters['{{baseName}}'] = <any>{{paramName}}.toISOString();
@@ -93,22 +93,22 @@ export class {{classname}} {
             queryParameters['{{baseName}}'] = <any>{{paramName}};
         {{/isDateTime}}
         }
-        {{/isListContainer}}
+        {{/isArray}}
 {{/queryParams}}
 
 {{/hasQueryParams}}
         let headers = this.defaultHeaders;
 {{#headerParams}}
-        {{#isListContainer}}
+        {{#isArray}}
         if ({{paramName}}) {
             headers['{{baseName}}'] = {{paramName}}.join(COLLECTION_FORMATS['{{collectionFormat}}']);
         }
-        {{/isListContainer}}
-        {{^isListContainer}}
+        {{/isArray}}
+        {{^isArray}}
         if ({{paramName}} !== undefined && {{paramName}} !== null) {
             headers['{{baseName}}'] = String({{paramName}});
         }
-        {{/isListContainer}}
+        {{/isArray}}
 {{/headerParams}}
 
 {{#authMethods}}
@@ -188,7 +188,7 @@ export class {{classname}} {
         }
 {{#formParams}}
 
-        {{#isListContainer}}
+        {{#isArray}}
         if ({{paramName}}) {
         {{#isCollectionFormatMulti}}
             {{paramName}}.forEach((element) => {
@@ -199,12 +199,12 @@ export class {{classname}} {
             formParams.append('{{baseName}}', {{paramName}}.join(COLLECTION_FORMATS['{{collectionFormat}}']));
         {{/isCollectionFormatMulti}}
         }
-        {{/isListContainer}}
-        {{^isListContainer}}
+        {{/isArray}}
+        {{^isArray}}
         if ({{paramName}} !== undefined) {
             formParams.append('{{baseName}}', <any>{{paramName}});
         }
-        {{/isListContainer}}
+        {{/isArray}}
 {{/formParams}}
 
 {{/hasFormParams}}
diff --git a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
index d3300f3906a..5fa20c944db 100644
--- a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
+++ b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
@@ -153,8 +153,8 @@ export class PetService {
         }
 
         let queryParameters = {};
-        if (status !== undefined && status !== null) {
-            queryParameters['status'] = <any>status;
+        if (status) {
+            queryParameters['status'] = status.join(COLLECTION_FORMATS['csv']);
         }
 
         let headers = this.defaultHeaders;
@@ -203,8 +203,8 @@ export class PetService {
         }
 
         let queryParameters = {};
-        if (tags !== undefined && tags !== null) {
-            queryParameters['tags'] = <any>tags;
+        if (tags) {
+            queryParameters['tags'] = tags.join(COLLECTION_FORMATS['csv']);
         }
 
         let headers = this.defaultHeaders;